Semi-Auto precision platform

E

eg23

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Hello,
I want to build up a good semi-auto precision rifle and I'm looking for some suggestions.
I all ready have an M14 build up but having a hard time getting the precision I want.
Is it better to go with a AR10 type rifle or another type that I may not be aware of?
If going with an AR10 type rifle, which is the better one to go with Armalite, DPMS....
Thanks for the help.
Eric
 
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From my M305, only thing I have done is stock replacement.

Then I developed load.

How precise do you want? Just curious.
 
That's outstanding!!
I don't reload so I have rely on commercial ammo.
As for you question(not sure if it was sarcastic or not) I'm looking for about 1MOA consistancy.
 
Generally, semi-auto and precision are not used in the same sentence. Sure, if you spend a lot of money/time you can get a semi to shoot very well. But you will never reach the same level of accuracy that is possible with a good bolt gun. If you want to build an accurate semi go for it, just don't complain if you can't get the groups as small as you want.:) Just my $0.02, YMMV

I see that you are looking for 1 MOA, if you through some money at a M-14 or AR you should be able to get that. But all I know I learned on the internet.:)
 
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Well I guess I'm looking for peoples opinions on each rifle. Especially the AR10 Type rifle because I think it would be a lot of fun to build one up. I know a M14 will never be as accurate as a bolt gun so I really don't need to start that argument again.
 
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I am sure M305 can delivery 1 moa. I developed load for 2 M305 already.

Above is another M305, I did it for a Chinese friend- you can see the Chinese bill with Chairman Mao's head on it. The load is 42gr Benchmark + 150gr Hornady FMJ bulk bullets!!!

It's a 8 rounds group. The plan was to shot a 10 round group. Too bad we screwed the 8th round. Then of course we stopped :)
 
Semi auto

I think dpms makes ar 10 type rifle in 260 remington .I think that might make a pretty good target rifle ,upgrade the trigger and stock and work up a good load then when its barrel is shot out go to a custom barrel.
cheers Tornado45
 
When I was playing with the M305's I was really impressed with how well they were built especially their chambers. They actually used a match chamber with the right throat and leade.

The M1A/M305 platform is ultra picky about ammo and bedding.

First, that action must be properly bedded.
Secondly, the gas system must be properly shimmed or welded up
Third, the trigger tuned for a better pull

Then properly loaded ammo tuned to the desires of the rifle must be used.

Benchmark, Fed 210M or CCI BR2, 155gr Amax/Bergers/Noslers in Win cases properly sized for the chamber.

When loaded properly, MOA or better is possible. I had lots of fun shooting and hitting clays at 400 to 500yds with mine.

As for other semis shooting well, you really need to look at what they are doing with the AR platform. Some manf are offering 1/2 min guarantees with test groups much smaller.

The gas rifle has come a very long ways. Of course, using BR quality barrels and proper chambers are a huge part of why these rifles can shoot.

Then they are shooting quality ammo/bullets instead of machine gun fodder.

The AR10 would be a very interesting but expensive rig to build.

PM me if you would like to discuss Shilen AR barrels.

Jerry

PS FN is now making a semi tactical rifle based off the Browning BAR hunting rifle that is supposed to shoot very well. Not sure if they will make it up here. Something else to research.
 
You haven't specified if you want to stick with a 308 but you mention AR10.

The AR platform with the right barrel is exceptionally accurate. The RCMP bought several Krieger barrels from me for their AR15's and tell me they are getting under an inch with various factory loads.

I've had several emails from AR15 customers that have reported under a half inch as the typical 100 meter grouping. Frankly, this surprised the hell out of me and i think i would like to see that first hand, but anything under an inch with a gas gun is pure gravy.

The M14 is used as a designated marksman rifle by the US military and they are using Krieger DMR pattern barrels.

Bottom line is the barrel being the biggest contributor to accuracy potential. Bedding and shimming are both important as well, but all the bedding and shimming won't help a crappy barrel.
 
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MysticPlayer/Jerry recommended a "tube gun" type rifle to me back when I came on here looking for suggestions on my first rifle and touted it highly.

Although I went with a bolt-action in the end, it might be an avenue you should consider exploring. MysticPlayer might have more to say on this.

I always thought headspacing was the biggest factor in sermi-auto accuracy; interesting how match barrels and chambers compensate for this...
 
Accuracy

If you want a non restricted SEMI AUTO the norc is the only way to go. The only downfall without a Viron barrel pressure bearing stock is the poi drop as the barrel heats. The poi change is greater than with a bolt gun.
A bolt gun is slower , holds more rounds , and kicks more.
Its all about your needs and desires --- :)
 
Well if you want to throw mega bucks at a semi auto in non restricted IE M14 here is what you need to change to get .5 moa consistently
Norinco M 14 500.00
McMillan or JAE stock 1000.00
SS Krieger HB +installation 700.00
Change Bolt & fit [USGI] 400.00
Modify gas system 50.00
Match spec break [ream out old one] 50.00
Good quality scope mount 400.00
Match oprod guide 80.00
But then again if you want to spend that much go ahead they can be fun to shoot but this set up requires constant attention
 
Obtunded said:
Bottom line is the barrel being the biggest contributor to accuracy potential. Bedding and shimming are both important as well, but all the bedding and shimming won't help a crappy barrel.
Click to expand...

I have to respectfully disagree given that this is talking about the M1A/M305/M14 rifle.

The best barrel in the world will do nothing if the rest of THIS rifle is not tightened up first.

This is no AR style free floating barrel, lazy man's bolt action rifle. There is so much slop in the system that can easily cause changes in barrel harmonics. Hell, it can easily change POA!

We know how critical a barrel is to maximizing performance in bolt action rifles but the assumption here is that the rest of the rifle is not flopping around like a dying salmon.

As for chamber being the root of accuracy, NEVER is - as long as it is cut true to the bore, it can be made to work. The bore itself and the stability of the barrel metal is what separates good from great.

The relationship of the bullet to the throat/leade has a bigger impact on accuracy then the chamber. The chamber is just the combustion area. The rest of the barrel takes care of the precision.

Note: not discussing the issues from the extractor groove back.

Most military barrels are far from consistent bore/land dimensions over its length. They may not be drilled true and are rarely stress relieved. Produced with the eye for low cost, high speed and long wear, bug hole accuracy is more a fluke then anything.

I would say of the M305's I tuned, not one shot worse then 1.5 moa at 200yds with most hovering in the MOA range (handloads of course). That was factory barrels, and bolts (I do not like USGI swaps and especially no 60's bent up op rod spring), using an affordable 2 screw scope base, shimmed gas system, and tuned orig trigger.

There is little doubt such a tuned rig with a Kreiger barrel should shoot that much better. However, we get to the land of diminishing returns where the platform becomes the biggest variable.

I have yet to meet an aftermarket stock that would do anything better then the orig style properly bedded. In fact, those that try and free float the barrel without other serious changes to the action, usually shoot worse.

YMMV.

Jerry
 
I have a DPMS LR-308 and an Armalite AR-10T on the way. I really enjoy shooting the AR-10 style rifles.

My set up. DPMS LR-308 24" stainless barrel 1:10 twist, RRA NM trigger (regular trigger isn't good for accuracy). Zeiss Conquest 6-20x 50mm Rapid Z 1000 yard reticle, Burris extreme rings. I had a PSG-1 style grip but it didn't work well with a front and back bag. I took it off and just use the stock pistol grip. I like the stock grip better.

I tried a bunch of different .308 ammo in this rifle. Surprisingly it shot the 155 grain Winchester slightly better than the 168 grain Federal Gold match :confused:. I wasn't too impressed :mad:. It was plinking accurate but not a precision rifle at all. I tried some Moly coated Norma 168 as well. So so. Then I tried my remaining 8 rounds of 167 grain Lapua. First 3 for sighters were right together touching :eek:. I shot one 5 round group with the remaining rounds. I was shooting in between 20 k/m wind gusts. The one flier was called, since the gust started up just before I shot. The gusts were going down range and slightly to the right. Anyways here's the rifle and here's a pic of the target. When I get some more Lapua ammo I'll give her another try. Plus I think I've narrowed the accuracy variable with this rifle. It's the fps. The lapua was over 100 fps faster than the Gold federal match. The 155 grain ammo was faster too. I'll keep this in mind when I start reloading.


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5 rounds, 100 yards 20 km/h wind gusts (trying to shoot during the calm in between the gusts). The 4 centre shots measured .650" edge to edge.

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This is the closest of the scope that I have. I don't own a camera or I'd take a few new pics. A camera is on my must buy list.

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redman said:
Too bad... your setup looks sweet.:cool:

I prefer a stock that has a hook/support type curve to put your non-trigger hand under, but that's just me.
Click to expand...

Thanks :)

I use a small bean bag under the stock and I squeeze the bag with my support hand to keep it dead on. Seems to work well. I find the A2 stock very comfortable to shoot in a target AR rifle. I considered changing it out for a Magpul PRS when I first bought the rifle, but I found that I liked the A2 one just fine. Plus I like the look of it :D. I should add that the sling connector on the back of the stock is rigid and does act a little bit like a hook for the bean bag. Oh well. Works for me and it doesn't cost anymore ;)

The only mods I can see in the near future are perhaps an Ergo grip for the pistol grip. Otherwise my money will go into target grade ammo (both off the shelf and reloading) and trying to get some more trigger time with this rifle. It really is fun to shoot. Even though it's restricted I'm a big fan of these rifles.
 
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