Need comments regarding load test results, group size, fps, etc. 308

I'm seating at 2.900" right now, I reckon 2800 fps is over max. I do get the occasional tighter groups, yesterday's .313 MOA group at 300m is an example, but also see more flyers, as yesterday's .6 and .7 MOA groups at 300m show. As much as I love the idea of 2800 fps out of a 24" barrel, I will likely be scaling it back, with 2700 fps being my sweet spot. Average groups may be a bit bigger but I'm hoping to get rid of the flyers. I would prefer a steady .5 MOA over the occasional .3 MOA.
 
I have a back up for my Varget load, using 175smk in Norma brass, with 43.7gr of H4895 and cci primers. At 2.835 it is running around 2650fps. This is out of a 24inch factory 5R (11.25). My throat, like yours, means I am jumping it out a ways no matter what. It was giving me sub minute accuracy and no pressure signs. It ends up being a bit dirtier than the Varget load but works well when components run dry.

I tried all sorts of seating depths, and nothing was working much better than what I had now, which functions flawlessly out of my dbm.

My rifle seems to like the 175-178 range to be just under 2700 and it seems to prefer the 168 class bullets to be about 2750.

Ymmv
 
RangerPark said:
I'm seating at 2.900" right now, I reckon 2800 fps is over max. I do get the occasional tighter groups, yesterday's .313 MOA group at 300m is an example, but also see more flyers, as yesterday's .6 and .7 MOA groups at 300m show. As much as I love the idea of 2800 fps out of a 24" barrel, I will likely be scaling it back, with 2700 fps being my sweet spot. Average groups may be a bit bigger but I'm hoping to get rid of the flyers. I would prefer a steady .5 MOA over the occasional .3 MOA.
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70 200 psi load approx, you are way over max 62 000
your max is 2700 fps with a 24 inch at 2.900

I wouldnt go above 2700 with your setup
 
I think that I'll go back to 2.875 also, more bullet in the case, might help with even ignition. I'll reduce charge accordingly
43.5 to 44.0 in .1 will be my next test.
bonus, fits mag.
 
RangerPark said:
Are you using QuickLoad? Just curious, I've been thinking of taking the QuickLoad plunge myself.
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yes, bought it from neconos.

It wont fix all your issues, but I like to know that I have a base line for experimentations.
Really helps when playing with OAL, charge, bullet types, etc.
Rifles tolerate some over charge, but it's not a good idea to load over max.
 
When I first shot this build I used reloads from my previous .308 because I didn't feel like taking those reloads apart. It was an older ladder with Berger 185's running from 41.6 to 43.2 gr of IMR 4064. I Immediately saw incredible results like 3 shot groups at .227 MOA at 41.8 gr, .364 and .333 MOA at 42.0 gr, .291 MOA at 42.2 gr and .379 MOA at 42.6 gr. Those would have been around 2600 fps. Seeing no signs of over pressure I pushed the load and found the upper node at 45 gr and 2700 fps. Ended up doing the same thing with the 175's at 46 gr and 2800 fps. I thought it was a safe load but I didn't notice the primers partly flattening until yesterday. I'm going to be pushing the lower node from now on. I'll trade 100 fps for safer pressures and better accuracy and consistency.
 
In my MDT .308 build, 28" heavy contour barrel 1:11, here are my best two loads:
(Lapua brass, CCI BR2 primers, Varget powder.)

178gr Hornady Match HPBT: 44.8gr Varget, 2830fps, .010 jump

208gr Hornady ELD's: 42.0gr Varget, 2575fps, .010 jump
 
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oh well I have my next 30 test rounds loaded at 2.875.
because I have not had good results at 2.950, I'm going back to a shorter OAL, hoping for more uniform initial pressure.

43.5 to 44.0, 5 rounds of each. will chrono and report groups. probably next friday.
 
I shot those test rounds and all groups are really bad, with flyers 2 inches off the other shot. Its all over the place.

I dont get it, the 168 grains at 2.800 shoot good groups, why cant I get those 175 tmk to shoot good groups?
Im not expecting .3 moa, but seriously, I am getting 2 inch groups with those so far, and best I got was a .8 moa group at lower velocity.

Wasnt able to get anything to shoot well at higher velocity.

Is my .250 freebore the issue? Should I just send that barrel to a smith to get a chamber recut with tighter specs?
I could also shorten it 2 inches to 24 instead of 26 maybe it would whip less?
 
Wow I'm sorry to read about that. My first .308 was a SPS Varmint with 26" 1:12" twist and it shot 185's at .5 MOA. I've always had good success with 175's and 185's. I've never tried 168's in any of my guns since the 185's always worked so well. Could be this gun just doesn't like 175's. I would try some 185's and 155's before thinking about a smith. Could be just a case of an average barrel too, it's probably fine for hunting. If you're going to spend the money to get the chamber re-cut you might as well look into a new aftermarket barrel.
 
If it were me, i would do one or a combo of three things - load to 2.80, lower load to the 41-42 gr node (2550-2600) fps, and would try a different primer - if using regular, try a hotter or mag primer -or- if using mag primers, go to regular... yea lots more shooting... if that didn't immed solve the puzzle, then i would do (pick your fave) ladder test/ocw (or variation) at 2.80 and try 4064, Varget, H4895, and R15 in that order... yea more shooting! Any of those powders will fill the case almost optimally full with bullet seated 2.8"
I have had 2 308 rifles that didn't like chasing lands with SMK or TMK's, and remarkably so. Maybe you have one.
 
I guess that I will go back to 2.800 and keep it there, and then ladder up .5 at a time from the lower node up to max and see

My rifle definitely shoots best at 2.8 no clue why.

Its an aics precision build for lr, heavy barrel with a large brake, so it wont be a hunting rifle ever.
 
Hi, I did some more shooting, here are the results.

Tested at 2.800 from 42.6 to 43.0
I was expecting higher speed but it went from 2655 to 2666, still low.
Results are horrible. Flyers everywhere, cannot group.

And, I did one more test. Load to 3.030 which is .010 off the lands.
Have to hand feed, but I always hand feed anyway. Bullet was still solid into the case.

6 rounds, Interestingly, it gave me a 3 shot group touching, and then 3 flyers.
Was a near max load, 44.5 at 2717 FPS.

Maybe I should try a next batch, touching the riflings and see ?
Wtf with the flyers everywhere? I mean, at that point, it's not a powder charge tweaking issue, bullets just fly everywhere.

I am really starting to wonder how I will get those bullets to shoot well.
I am only interested in a near max load as this is for 1000m shooting.

Ideas ?
(I'll shoot a group of my 168 grainers next time just to confirm that it's not the rifle or the scope... something has to group).

175_tmk.jpg

175_tmk_close.jpg
 
Wow ok. Anything worth looking at on the rifle itself? Action screws loose or unevenly torqued? Same deal with scope base and rings screws? Defective scope, won't keep zero? At this point I think you should get some reputed quality factory ammo, like Federal Gold Medal match for example, and try those out first. If that's all over the map too then I would think there's something going on with the rifle. If the Gold Medal ammo shoots well then you can try to duplicate that and work from there.
 
Yup probably what I will do, at that point I don't trust the rifle seriously.

I even disassembled the aics yesterday, cleaned the rifle, and reassembled, torqued, shot 5 shots today, re-torqued (53), still shot bad, I torqued a bit more to 65, still shot bad.

Yup, at that point I'll shoot my last 168 grainer loads next time, and a box of match ammo and then see.

I did not re-check the scope base, but they were torqued to spec with blue locktite, and the rings were lapped and they are torqued to spec, and nothing moves on that.

IF the factory ammo groups bad after 5 shots, I'll disassemble the scope.

Scope is a signtron S3 8-32x56

But I think that before I can shoot loads that are known to group in my rifle, it's not worth arguing over the bedding or the scope I guess.... I just have to shoot rounds known to group and see if they group or not.

I know, it's really bad, I've shot 200 of those so far with ####ty groups.
I've never seen a rifle group so bad with any of my hand loads ever.

But if you look at my first pics, the 168 grain groups werent too bad with a .8 10 shot group.

If the rifle does it again, it's fine...
 
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It can be really frustrating for sure. A defective scope is the hardest to diagnose, you need a proven spare scope to compare. Some guys have spent tons of money developing loads, trying to make a rifle group only to realize their scope wouldn't hold a zero.

In your case it might be worth it to get the stock secured in a vise, and then place a dial indicator on the barrel to see how much it moves when you torque the screws. Could be a bad mating between the action and barrel, but with an AI that's unlikely. Other than that I'm out of ideas.
 
were your targets mounted the way the pics are (horizontal/landscape)? if so, thats a lot of vertical - i would be checking for a mechanical issue. Failing that, do you have another stock you can drop the action in to verify?
I guess shooting your standard 168 gr loads should tell you a lot - but if its out too, then i would look at the stock.
 
Yes, the targets were mounted that way.
Horrible vertical yes.
Wont be able to shoot again before probably 2 weeks though, so I will not be able to provide results soon, sorry.
I might just double check the scope mounting tightness in between, nothing to loose.
 
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