DI Precision

[redshooter]

Over the years it has become very clear to me that many Black Gun shooters are completely unaware of what Mr. Stoner's creation is capable of. If the rest of you will indulge me, I'd like to see if we can get a collection of tips/tricks to improve the accuracy of DI Rifles, in particular rifles based on the AR-10/AR-15. I expect the bulk of the discussion to be about rolling your own, but since a semi-auto is more complex than a bolt gun I hope the talk also covers ways to mitigate problems created by slop between the upper and lower etc.

The goal isn't to show off how your rifle groups, but to make it shoot groups worth bragging about.

The AR-15 is an inherently precise rifle, two of the three I've owned have been capable of sub MOA performance. The third may have been, but I never had it long enough to find out. People commonly state it's a 2 MOA platform I disagree.

That's 5 shots 100 yds, can I do that every time, no. That said I've fired enough sub MOA groups that I can safely say the rifle is sub MOA if it gets the right load. In this case 75gr Hdy HPBT's and 22.5gr of H 4895.

Here's where I need help, the guy driving. This is 20 shots fired at 100 yds, same load as above. I fired 5, walked down and back, fired 5 more, etc. (I need the exercise). Note that there are 4 distinct groups.

I'm sure the drifting of the groups was caused by my bubba'd cheek riser, it was not securely fixed to the stock.

Please add anything you KNOW helped improve how your rifle grouped, for example I changed to a free float forearm and groups off a bipod shrunk from 2 MOA to 1 MOA. I'm especially interested in how to tighten up how the upper and lower mate...for those that say it's irrelevant F Class shooters would likely disagree, they don't bed their rifles because they are bored (that in a platform where no movement is detectable before the bedding). I also suspect that how I rest my forearm on the bag has some influence. If anyone has experimented with where they mounted a bipod on an A2 forearm I'd love to know your results.

EDIT, we have had a minor impasse over tolerances and the effect on accuracy, if anyone can expand on one side or the other feel free, but please go through the posts to see if it's already been presented. I still say it matters, but I'll concede it probably has an insignificant effect on the rifle, the shooter another story...once I take the magwedge out I swear I could almost shoot around corners, it's in there if for no other reason to limit the movement of 2 steel pins in 6 aluminum holes (one has a bushing). Take care of your rifle and it will take care of you.

 

[cr5]

Upper and lower tightness does not effect accuracy, at least not enough for the average shooter to worry about. Perhaps at the upper levels of competitive shooting it might make a difference but it would be like putting one of us in a Ferrari on a race track and seeing the different lap times between brand A race tire and brand B race tire, we couldn't drive well enough to tell the difference so it's a non issue. Comparing it to an F class rifle is apples and banannas, no relation. I've owned AR's that were very tight with almost no wiggle at all that shot 2 moa and AR's that were pretty sloppy in the upper/lower fit that would shoot sub moa, it's more about barrel quality and compatible ammo than a little wiggle between the upper and lower.

The things I've found that have the most influence on AR accuracy other than shooter skill are barrel, ammo, and optics choice, a nice trigger makes things easier but I've shot some really tight groups with a standard milspec 2-stage trigger. You'll have a really hard time shooting tight groups with a red dot that has a 4moa dot or if you're using a crappy scope that has poor glass or a crappy reticle.

To make an AR shoot tight groups a free floated forend helps but is not critical, my PWS 11 inch piston driven AR has shot moa with good ammo off a solid rest. And it has to be the worst combination being non free floated and having a long stroke piston system. It does however have a premium quality button rifled barrel.

How you set it in the bags or on the rest has less to do with accuracy than just doing it the same way every time. Consistency is your friend in accurate shooting. Do it the same every time once you find a way that feels comfortable and repeatable.
Run quality optics, a premium barrel, shoot from a solid rest, take your time, and find a load the barrel likes and if you do your part pretty much any AR will shoot 1 moa or better.

 

[Mystic Precision]

sub 3/4" CGN AR15 Challenge done for 2106 - I think my 45rds (9 group) average was around 0.65"

The Rifle I did it with... McGowen match barrel, Norc M4 mechanicals, tweaked buffer system, Magpul grip and stock, free float HG by YHM, MPOD, Dlask muzzle brake, handloads. Yes, the base is the "lowly" Norinco CQA.

Handloads used Bergers, CCI primers, Win brass, Varget.

Nothing really out of the ordinary. Just putting good parts in the right places and tune accordingly.

Testing the new Nosler 70gr RDF and it looks really promising. Don't have my last 5 shot group picture (was around 5/8"... see my facebook page) for the load I will try for the CGN challenge for 2017

Nice looking bullets and seem to like my rifle.

As cr5 has indicated, the tech to help an AR shoot is very well developed given the massive useage in the US. All you need to do is research US High Power shooting or the AMU or Creedmoor Sports... there is an entire industry dedicated to this very large sport and all manner of goodies are possible.

Where I put my efforts... quality barrel - there is alot of really poor quality barrels with the "match" title put in the description. Chambers, bore tolerances, finish, machinining can be "factory" barrel type quality... but they are well priced.

I can offer Shilen, Krieger and McGowen. McGowen is the "lowest" match barrel grade but still plenty accurate when set up properly. Shilen and Krieger are simply top tier US brands with Shilen pretty much dominating the 2016 CMP national rifle match with 5 of the top 6 shooters using these barrels. Pricey, you bet but quality match barrels ARE expensive.

Air gauged, lapped, stress relieved Match quality barrels properly chambered and assembled. If a low grade blank is used, all the fancy machining and colouring is not going to help.

I believe a Cdn DCRA SR score record was shot with a Krieger a year or two back.

Unfortunately, there is alot of interest to have a precision AR but little effort to use the right parts.

Same for tuning the reciprocating bits, and proper handloading... gas operated rifles NEED a different approach. The AR is one of the most forgiving systems for Factory ammo and some combos do work but use the right components to help the system work in concert is needed to get the most of this set up.

it will be more fussy then a bolt action rifle BUT accuracy approaching 1/2 MOA is possible.

Jerry

 

[Mystic Precision]

redshooter, please don't take this is a slight or being mean but the 20rds group you shot IS representative of the accuracy performance of your barrel and rifle. This is what your rifle is really doing and it is not sub MOA. I have to assume you kept the same POA and didn't guzzle 5 red bulls before each group?

I am unsure if you have had a chance to shoot a true match rifle with quality barrel? If you look at my 5 group target, the impacts are pretty much in the same place relative to the center of the black diamond.. any lateral movement is due to wind. Vertical is due to changing POA and resetting body position... I do a rest after each 5rds group to let the barrel cool. With a collapsible stock, I expect some POI shift when you reset.

With the right type of barrel, your groups are going to overlay on the same place on the target (given condition changes)... from this, you can get a true average of what your barrel can do over extended strings and if the barrel will change as it heats up.

You can easily replicate the CGN challenge and confirm what your rifle will or will not do. With a target with a few aiming points, ideally all horizontal. Put up some wind flags or shoot on a calm day. Same aiming point on the target. Take your time and shoot your groups.. DON'T go down and view your target. This is a test best done blind. After you have shot your 3, 4 or whatever number of groups, THEN go down and see what you got.

Write notes of what the air is doing and if you pulled any shot in any group and where you think that shot should have gone ie pulled high, pulled left, etc. If the rifle is consistent, that shot is going to be where you expect it to be. Pulled high left on shot 3... go see target and there is 4rds in a cluster with a shot high left.. THIS is a good barrel and load.

it is all too common for shooters to blame themself for the poor performance of their rifle. From helping a number of shooters over the years, I can tell you their "mediocre" skills suddenly improve when put behind rifles that actually work (Yes, they get to shoot my toys).

AR15's are capable of some very exciting accuracy... most off the rack ARs don't shoot that well.

YMMV.

Jerry

PS, I definitely recommend a Free float type HG. if not confident in using a folding bipod, use sand bags or a rigid F class type bipod. My upper and lower are typical Norc M4 but I do have an accuwedge in between... pretty tight. Were you using a scope? If yes, do you know if it will hold a consistent POA?

 

[beltfed]

Many years ago a high power shooter and gun writer Glen Zediker did a pretty succinct book on the AR-15 and wringing the most from the platform.
He has done a few more since that time as well.
They are a good read, combine the opinions, experience and knowledge from many well known names, and probably not surprisingly contain very little internet b/s.
I highly recommend them.
www .zediker.com/books/ar15/ar15main.html

A summation in one sentence reflects what has already been said: Float a good barrel and run premium ammo (of course good optics and trigger go a ways too).

 

[redshooter]

redshooter, please don't take this is a slight or being mean but the 20rds group you shot IS representative of the accuracy performance of your barrel and rifle. This is what your rifle is really doing and it is not sub MOA. I have to assume you kept the same POA and didn't guzzle 5 red bulls before each group?

I am unsure if you have had a chance to shoot a true match rifle with quality barrel? If you look at my 5 group target, the impacts are pretty much in the same place relative to the center of the black diamond.. any lateral movement is due to wind. Vertical is due to changing POA and resetting body position... I do a rest after each 5rds group to let the barrel cool. With a collapsible stock, I expect some POI shift when you reset.

With the right type of barrel, your groups are going to overlay on the same place on the target (given condition changes)... from this, you can get a true average of what your barrel can do over extended strings and if the barrel will change as it heats up.

You can easily replicate the CGN challenge and confirm what your rifle will or will not do. With a target with a few aiming points, ideally all horizontal. Put up some wind flags or shoot on a calm day. Same aiming point on the target. Take your time and shoot your groups.. DON'T go down and view your target. This is a test best done blind. After you have shot your 3, 4 or whatever number of groups, THEN go down and see what you got.

Write notes of what the air is doing and if you pulled any shot in any group and where you think that shot should have gone ie pulled high, pulled left, etc. If the rifle is consistent, that shot is going to be where you expect it to be. Pulled high left on shot 3... go see target and there is 4rds in a cluster with a shot high left.. THIS is a good barrel and load.

it is all too common for shooters to blame themself for the poor performance of their rifle. From helping a number of shooters over the years, I can tell you their "mediocre" skills suddenly improve when put behind rifles that actually work (Yes, they get to shoot my toys).

AR15's are capable of some very exciting accuracy... most off the rack ARs don't shoot that well.

YMMV.

Jerry

PS, I definitely recommend a Free float type HG. if not confident in using a folding bipod, use sand bags or a rigid F class type bipod. My upper and lower are typical Norc M4 but I do have an accuwedge in between... pretty tight. Were you using a scope? If yes, do you know if it will hold a consistent POA?

None taken Jerry! In the case of the 20 round group, I'm 99% sure it's me. One of my problems is I seem to have a hard time maintaining a consistent hold. In this case it was made worse by a jury rigged cheek riser sliding around and a 1-4x24 mounted on an NcStar carrying handle mount (the combo is surprisingly good). The 1/2 dozen sub MOA groups I'm claiming are not included in that 20 shot string. As this thread applies to me, it's about my shooting and how I interact with the rifle, not the rifle/ammo. A few of the things I'm considering doing to improve my consistency is some form of hand stop on the forearm to improve my offhand shooting, and muzzle brake so I can better identify when I've failed to manipulate the trigger properly. I really need some instruction, but the opportunity hasn't presented itself yet. Perhaps I'll attend a course at Milcun...it's less than an hour away.

Thanks for bringing that book to my attention beltfed, I have no doubt that I could find all the details about my questions by spending an afternoon with google. The hard part would be filtering out all crap and hocus pocus...I know the players here so to speak.

cr5, optics is one of those places where I'm hobbled gear wise. My Scopechief is surprisingly good, but it seem like I need at least 10X and a fine reticle to perform at my best. My favorite scope that I've been able to afford over the years was a Bushnell 6-24X40 with a 1/8 MOA dot cross hair. I wish I still owned it, but with my limited resources I end up having a high turnover when it comes to gear. I've been lucky this year, haven't had to pawn anything important to me.

 

[Sqr]

IMO the order of a precision AR components are:

>Barrel (bolt matched to the barrel extension) jury is out on crown or with a muzzle device. Run and Gun a brake is imperative.
>Optics
>gas system (a tuned rifle requires a good buffer system, adjustable gas block, bolt carrier *weight*)
>Free floating hand guard (with barrel nut installed correctly - torque)
>Ergonomics (stock and Grip, Bipod with stock mono pod)
>Trigger (consistent trigger weight)
>Receivers (slopping fitting receivers may affect run and gun shooters more then it can bench rest disciplines......this is mostly a mind game thing)

Technique - this can be a deal breaker regardless of the equipment used.

Reloads with the correct bullet weight and dimensions geared to a particular barrel twist and R's.

 

[beltfed]

I have no doubt that I could find all the details about my questions by spending an afternoon with google. The hard part would be filtering out all crap and hocus pocus...

This is why I suggested the book.

IMO the order of a precision AR components are:

>Barrel (bolt matched to the barrel extension) jury is out on crown or with a muzzle device. Run and Gun a brake is imperative.
>Optics
>Technique
>gas system (a tuned rifle requires a good buffer system, adjustable gas block, bolt carrier *weight*)
>Free floating hand guard (with barrel nut installed correctly - torque)
>Ergonomics (stock and Grip, Bipod with stock mono pod)
>Trigger (consistent trigger weight)
>Receivers (slopping fitting receivers may affect run and gun shooters more then it can bench rest disciplines......this is mostly a mind game thing)

See, stuff like tuning the gas and lapping in of bolts, and critical torque of the barrel nut - herein enters the internet.

A lot of this stuff was tried and tested in the early days of the USAMU and marine teams shooting the AR in their competitions. Sh!t that was tried, tested, re-tested, tested again 'cause all they do is shoot and then tested again for sh!ts n' giggles and still deemed to not matter one iota.
If tuning the gas system keeps your brass in one itty bitty pile or helps you with your head game - more power to you - keep on keeping on. But to suggest it has any relevancy with how the gun performs on target - well, let's all see the data.

 

[redshooter]

Guess I can add to my own thread...

I have an A2 upper and go from irons to scope depending on my mood (or how my eyes are doing that day). A fellow club member and Service Rifle shooter was watching me screw about with my homemade cheek riser and suggested I use Vet Wrap to secure it to the rifle. I purchased a semi-closed cell foam kneeling pad cut an appropriate piece and secured it with the Vet Wrap he gave me. This stuff is great!

How does it help? It stays put and has a nice comfortable surface.

As for stuff like slop, tuning, lapping, etc. I have no doubt it would help, but for one undeniable fact, this isn't Benchrest, so it probably is meaningless in the relm of this discussion.

 

[Mystic Precision]

This is why I suggested the book.




See, stuff like tuning the gas and lapping in of bolts, and critical torque of the barrel nut - herein enters the internet.

A lot of this stuff was tried and tested in the early days of the USAMU and marine teams shooting the AR in their competitions. Sh!t that was tried, tested, re-tested, tested again 'cause all they do is shoot and then tested again for sh!ts n' giggles and still deemed to not matter one iota.
If tuning the gas system keeps your brass in one itty bitty pile or helps you with your head game - more power to you - keep on keeping on. But to suggest it has any relevancy with how the gun performs on target - well, let's all see the data.

how come there are adjustable gas blocks and a variety of options for controlling the gas flow through the gas tube (this stuff is kind of hokey but someone has been playing)? Why does my rifle length barrel have a mid length gas port? Wasn't my ideas or invention... just using US tech.

From my testing and tuning, I use what I have found to matter. Different end uses will have different needs and wants.

the USAMU guys do a TON of research and have moved the Service rifle platform miles ahead of what Stoner offered BUT the performance continues to move forward and sometimes, it is the civi arena where break throughs happen.

It is always nice to see them, and now other US military shooting squads show up to the bigger US F class matches. They come to see and learn from top US shooters. They have learnt alot from them and applied that tech into what is currently in service. The same goes for the PRS game.... not all knowledge is govt financed.

put some of your theories to practise and try out the 5X5rds challenge. That is the best way to figure out what does or doesn't work don't you think?

I don't run and gun.. I paper punch and have spent a good long time investigating and testing a wide range of stuff. The proof is small groups on paper. Are there other ways to reach the same destination ABSOLUTELY.... Pick a formula, build a rifle and go shoot it. Post your results.

YMMV.

Jerry

 

[Mystic Precision]

None taken Jerry! In the case of the 20 round group, I'm 99% sure it's me. One of my problems is I seem to have a hard time maintaining a consistent hold. In this case it was made worse by a jury rigged cheek riser sliding around and a 1-4x24 mounted on an NcStar carrying handle mount (the combo is surprisingly good). The 1/2 dozen sub MOA groups I'm claiming are not included in that 20 shot string. As this thread applies to me, it's about my shooting and how I interact with the rifle, not the rifle/ammo. A few of the things I'm considering doing to improve my consistency is some form of hand stop on the forearm to improve my offhand shooting, and muzzle brake so I can better identify when I've failed to manipulate the trigger properly. I really need some instruction, but the opportunity hasn't presented itself yet. Perhaps I'll attend a course at Milcun...it's less than an hour away.

....

Consider using quality rings and mount directly to the upper.. If there is any play at all in your mount (like 1 thou), it will change the scope POA. Optics need to be solidly mounted to any platform. a 4X scope may limit the resolution you can see on target. maybe going to a proven higher mag scope may help you see and aim better... at least for the testing phase.

There is no doubt that position behind the rifle matters and will affect POI so get that squared away first. Then work on solid support for the rifle so you are consistent in your follow through. When testing, we want to reduce the influence of the shooter as much as possible. A bunch of sand bags out front and another under the butt stock will do wonders. When you are looking at the target, the reticle should be steady on your aiming point. Breath, squeeze, bang..... repeat.

You have proven you have the skills to shoot sub MOA... now prove that the rifle will do it consistently. If you know you have made a good pull and the shot goes somewhere else, this is more then likely the rifle/ammo and not you. Focus on making perfect shots in as long a time as it takes. Once you know you have done all you can to make a perfect shot each and every time, if the results on paper aren't to you liking, consider tweaking the gear.

Loose rails, rings are an all too common problem in groups shifting around a target. Scope failures are too. Some budget stuff can wear and loosen with use. Cheap can be real expensive if it creates inconsistency in your platform.

This is not a contest just an opportunity to improve ones skills and confidence. The rifle/ammo combo either will or it will not.

I bet you are a better shooter then you give yourself credit.

Good luck...

Jerry

 

[Olyar15]

Alternatively, you can just suck it up and put down the cash for a Les Baer AR.

 

[Sqr]

how come there are adjustable gas blocks and a variety of options for controlling the gas flow through the gas tube (this stuff is kind of hokey but someone has been playing)? Why does my rifle length barrel have a mid length gas port? Wasn't my ideas or invention... just using US tech.

From my testing and tuning, I use what I have found to matter. Different end uses will have different needs and wants.

the USAMU guys do a TON of research and have moved the Service rifle platform miles ahead of what Stoner offered BUT the performance continues to move forward and sometimes, it is the civi arena where break throughs happen.

It is always nice to see them, and now other US military shooting squads show up to the bigger US F class matches. They come to see and learn from top US shooters. They have learnt alot from them and applied that tech into what is currently in service. The same goes for the PRS game.... not all knowledge is govt financed.

put some of your theories to practise and try out the 5X5rds challenge. That is the best way to figure out what does or doesn't work don't you think?

I don't run and gun.. I paper punch and have spent a good long time investigating and testing a wide range of stuff. The proof is small groups on paper. Are there other ways to reach the same destination ABSOLUTELY.... Pick a formula, build a rifle and go shoot it. Post your results.

YMMV.

Jerry

I have noticed an increase in accuracy when the gas block has been completely closed rendering the DI as a bolt gun.

Gas block closed

Gas block open

100 yds with identical setup as above.

 

[Mystic Precision]

Sqr, you have a superbly shooting AR and in such a novel chambering... just COOL!!!!

if multiple groups gas on vs gas off show gas off offering the smaller groups, try playing around with your BCG, Buffer and buffer springs.

Things are moving a fraction of a second too soon and the barrel vibration is being affected.... although the difference in the groups pictured is awfully small. personally, I would retest several times just to see the average cause a bug fart could move you out that far

Maybe open the gas block in really small increments until it just functions... if the flyers go away, then you have your answer on where to look for solutions.

I hope that you will try the CGN challenge and get a 5X5rds average close to 1/2" average.... that would be AWESOME.

Jerry

 

[Sqr]

Sqr, you have a superbly shooting AR and in such a novel chambering... just COOL!!!!

if multiple groups gas on vs gas off show gas off offering the smaller groups, try playing around with your BCG, Buffer and buffer springs.

Things are moving a fraction of a second too soon and the barrel vibration is being affected.... although the difference in the groups pictured is awfully small. personally, I would retest several times just to see the average cause a bug fart could move you out that far

Maybe open the gas block in really small increments until it just functions... if the flyers go away, then you have your answer on where to look for solutions.

I hope that you will try the CGN challenge and get a 5X5rds average close to 1/2" average.... that would be AWESOME.

Jerry

Items I have tried:

FA, SA and SP1 bolt carrier
Rifle buffer in standard weight, one and two aluminum weights with steel, rifle H
Warn out buffer spring, new spring and new spring with 1-4 coils incrementally cut off
Rifle length Gas port enlarged from standard size to the current .125
Now trying JP Silent Captured Spring system
JP clamp on adjustable gas block
Ultra low profile gas block.
Melonite and SS rifle gas tubes.
Multiple CAM pin brands.
Lubed With grease and with oil.

With a number of the listed combinations.

AR's can be accurate.

The centre group are the different bullet weights I have fired out of this Jury Custom 20" barrel.

 

[beltfed]

how come there are adjustable gas blocks and a variety of options for controlling the gas flow through the gas tube (this stuff is kind of hokey but someone has been playing)?

Predominantly these sprung up due to the use of suppressors.


Look, I didn't post to be a Debbie downer - I've done a fair bit reading on what has been tried and a fair bit of testing on my own. I too have tested stuff or processes to confirm or to question what others have said or done.

If playing with the gas settings and cutting coils off recoil springs floats your guy's boat, go for it.

- cutting the gas might change the velocity a bit, but predominantly if it has any effect, it will be that of the shooter's follow through.

SQR - honestly - the cam pin? You are spinning your wheels dude. Concentrate on your hand loading, you already have by the looks of it, a decent gun and and great performing barrel.

 

[Sqr]

Yes the cam pin is over the top but some brands have demensions that are slightly different so I tried them to see if the locking action could be made smoother. These subtle experiments are to try tuning the functioning for shooter comfort which "may" lead to an increase in performance.

Oh I continue to work on my loads with 322, 335, I4198, H4198, 4895, AA1680, AA2200, RL7, RL10, 2400, I3031, H110 and a few other powders I can't remember. Hornady, SSA and Remington brass with large and small rifle primers pockets. Standard and Magnum rifle primers along with alternate brass lengths. Bumped the shoulders and tried no crimp, roll crimp and taper crimps.

Shooting for me isn't just at the range but time spent in the Man Cave toiling over ideas.

 

[Mystic Precision]

Predominantly these sprung up due to the use of suppressors.


Look, I didn't post to be a Debbie downer - I've done a fair bit reading on what has been tried and a fair bit of testing on my own. I too have tested stuff or processes to confirm or to question what others have said or done.

If playing with the gas settings and cutting coils off recoil springs floats your guy's boat, go for it.

- cutting the gas might change the velocity a bit, but predominantly if it has any effect, it will be that of the shooter's follow through.

SQR - honestly - the cam pin? You are spinning your wheels dude. Concentrate on your hand loading, you already have by the looks of it, a decent gun and and great performing barrel.

Ah, but invented for one useage can have a wonderful effect of solving another. I believe JP was the first to make adjustable gas blocks. They are in the race gun business not the jump out of good airplanes business (at least not primarily).

Consider that for pure accuracy, we use bolt action rifles. Solid lock up, very simple physics, nothing to screw things up. Now a semi, adds this little problem called auto cycling... not so simple physics, lots to screw up. What if you turned a semi auto into a two part device? Bolt type harmonics while the bullet is flying down the barrel. Self cycling when the bullet has left the muzzle? At worst, "gentle" and consistent cyclic forces so you can adjust the ammo to suit.

That was my approach to all my semi work over the years. Surprisingly, it actually did work and above par accuracy was offered. Now of course, quality of barrel, chamber, etc, etc come into play as well. The platforms that went very well were the M305 and the AR with DI (never played with a piston AR rifle).. Other semis, didn't fare so well cause they had their own limitations mainly around the supplied barrel.

A local shooter took my approach and turned his HK SL8 into a 1000yds zapper... pizza box accurate at that distance... Amazing to watch.

It is NOT how you want to set up your working rifle but if you are just building a range toy, lots of performance on the table.

Sqr, consider the heaviest buffer and MORE spring... you want to keep that bolt locked as long as possible. your ammo has alot more mass then a 223.

Jerry

 

[Mystic Precision]

Yes the cam pin is over the top but some brands have demensions that are slightly different so I tried them to see if the locking action could be made smoother. These subtle experiments are to try tuning the functioning for shooter comfort which "may" lead to an increase in performance.

Oh I continue to work on my loads with 322, 335, I4198, H4198, 4895, AA1680, AA2200, RL7, RL10, 2400, I3031, H110 and a few other powders I can't remember. Hornady, SSA and Remington brass with large and small rifle primers pockets. Standard and Magnum rifle primers along with alternate brass lengths. Bumped the shoulders and tried no crimp, roll crimp and taper crimps.

Shooting for me isn't just at the range but time spent in the Man Cave tolling with ideas.

That cam pin IS important IF it doesn't fit your receiver and rubs and drags in an inconsistent manner. I am digging all the experimenting you are doing. That is how you learn. My guess is that the best combos all work about the same with nothing really head and shoulders above the rest?

AT some point you hit the mechanical limits of the barrel and set up. An AR is not likely to average sub 1/2MOA regardless of what we do. precious few will average 2/3 min. But it would be great if we can figure out a process that does....

Jerry

 

[redshooter]

Shooting for me isn't just at the range but time spent in the Man Cave tolling with ideas.

If I can't reload for it I'm not interested in shooting it, part of why I own no functioning rim fire. I'd be doing the same thing if $$$ allowed, sad thing is if I had the cash I wouldn't have the time.

Consider that for pure accuracy, we use bolt action rifles. Solid lock up, very simple physics, nothing to screw things up. Now a semi, adds this little problem called auto cycling... not so simple physics, lots to screw up. What if you turned a semi auto into a two part device? Bolt type harmonics while the bullet is flying down the barrel. Self cycling when the bullet has left the muzzle? At worst, "gentle" and consistent cyclic forces so you can adjust the ammo to suit.

This reflects my opinion on the matter, everything you do will have an effect on how the different parts interact, be it material, it's dimensions, etc., eventually you have to ask is it worth the expense and effort...I think Sqr might be getting close to that point.