Woa 10 twist 20 prac load woes

varminter .223

Active member
Ive got about 150 rounds down the 24" bull pipe now and while I've shot a few good 5 shot groups I can't seem to get repeatability. Just curious what bullets you guys have had luck with on a 10 twist. I put in an email to White Oak but haven't heard anything yet. The only thing that has shown any consistency so far has been 35 bergers and benchmark. Im seating the 35's at 2.210" which puts the ogive the same spot as 39's at 2.260". That puts bullet about .135" into the case. Cleaning every 25 or so with wipe out. .226" bushing with expander ball gets me .0025" neck tension. I don't think oal is changing while the round is chambering. I did have one get caught on the feed ramp and get shoved clean into the case. 39's show little vertical spread over a wide range of powder charge but random 1.5" horizontal spread.
The only critters I shoot with a rifle are coyotes so I don't really need to be shooting bullets for small vermin.
 
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Are you shooting off a bipod and rear bag? The AR platform can be tough to shoot consistently, form and technique are much different than bolt guns. If I haven't shot my AR's for a couple months it takes a few rounds to get smooth. Horizontal strings for me 1. Not reading wind correctly 2. Trigger operation.
 
Well I have a slew of other ar's that I don't seem to have an issue with using the same technique. As far as what I'm shooting off of. I have shot it off bags and my lead sled solo. The same setup I was shooting 5/8 in three shot groups with a pencil barrel axis the other day so I don't think technique is the issue. For example it will put four in one hole then it will throw one an inch high and left...... I load 5 more of the same load and it looks like you shot him down there with a shotgun at about an inch and a half with no rhyme or Reason to where they're at.
I should also add I've even put it on a different lower that fits tighter at the pens to clean up any slot between the upper and the lower as well as trying to different scopes a V16 and now I have a 6.5 x 24 Brunton on it.
As far as triggers go, I won't even waste my time or a bullet if it doesn't have a quality trigger. Most of my rifles have Geissele sd-e but I'm growing fond of my 3 lb velocity after receiving several super dynamic enhanced triggers with either too light of a second stage or travel.
My next step may be to remove the Bear Creek Arsenal handguard and try a spare Matrix I have laying around to eliminate and out of square barrel nut. I lap all my receivers as well.
 
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Different bullets show different patterns of inconsistencies as well. I would imagine improper technique wouldn't have inconsistencies that follow bullet type.
 
My 20 Prac with a 1:10 Shilen barrel shoots the Berger 40 grain bullets very well over a stout load of Benchmark.

Build some dummy rounds and cycle them through the rifle and see if the OAL changes to ensure the 0.0025 neck tension is enough.
 
I have just started with 20 calibers in Ar, My 20x6.8 in a 10 twist doesn't shoot the Berger 40's except in a bout an inch and half size group. The Hornady 40gr VMax will shoot 1/2" or smaller with the same load. I necked my cases down from 6.8 so I believe I could have thick neck problems, I get better groups with the inside neck ream before I seat a bullet on any bullets.

The little cases can build pressures very rapidly with just a tenth of a grain powder difference as well. If you are using a chronograph you can watch the sd. Also watch where your ejected cases go, they should make a small pile if you have a solid hold on a group, each gun is some different here, but they should all land fairly close.

Use a cleaning product that takes out carbon and don't try to strip out the copper fouling, see what that does.

Also seat try seating the base of the bullet down to the bottom of the neck rather than using over all length. Look at factory Ruger 204 ammo and you will see the difference.

I have a 204 Ruger with a 10 twist that shoots either 32 or 40gr factory ammo in almost the same hole and a nice 1/2" group, looks like the bullets are extremely short but they shoot.

The 20 caliber has been confusing for me.
 
Odd that you can develop a load with minimal vertical spread and consistently have a horizontal spread. Possibly have crown checked . I have had good luck with 8208 with both the 35 Berger and the 39 Sierra in a couple 10 twist 204r barrels.
 
40gr Nosler and 39gr Speer work very well in mine. Use 8208, H4895 and A2520 powders. I had a BHW 20P barrel that I was fighting the same thing...I would shoot several groups and then clean it, shoot more groups and clean...a friend suggested to quit cleaning it so much...started just shooting it and not cleaning and it started shooting very well and consistently under 1/2". I have a DTECH 20P as well and do the same with it...just shoot it...maybe clean it after 100 or more rounds. Never did clean it thru the coyote season and never had any issues. Just use a chamber swab and swab out the chamber periodically thru the season.
 
Varminter, another thing I forgot to mention was that I originally started using LC 223 brass for my 20P...everybody rants and raves about how good it is...when I was going thru the issues with mine, I decided to weigh some casings and after this eye opener, I opened a new bag of Winchester 223 brass, necked it down and saw an instant change for the better in my groups...a lot more consistent. Just throwing that out there as another possible issue to look at.
 
Any updates on your WOA? I have a 20" varmit profile, but it is 1-7 twist so my load data wouldnt help. I am getting sub MOA consistently with most loads i throw down the pipe. Hopefull you find the right combo or the issue
 
10 Twist with BHW Barrel AR loves 40grain pills with Benchmark 25.5 grains. Shoots the smaller stuff ok but not like the 40s
 
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Well it shot 40 bergers with 24.5 Benchmark terrible so I switched back to the 35's and 25.5 Benchmark. I put it on an omni hybrid polymer lower which has zero lateral slop at the front pin. I began seating the bullet so the bottom of the bullet is all the way to the bottom of the neck for max retention. It seems to be holding under an inch for 5 shots now. Horizontal spread was the worst part and I was shooting in a fairly stiff varying left to right wind and so Id say its acceptable now. I am confident the .003" or so slop between between the upper and the lower at the front take down tang has been the source of some of my AR accuracy frustrations. Just dry fire about ten times while aiming from a bench and watch the crosshair jump back and forth. Im convinced when the hammer which is in the lower strikes the firing pin in the upper it cause the upper to shift in relationship to the lower at the pins which equates to an inch or so poi shift at 100 yards. Switching to the polymer cleaned up some of the same issues on my woa 22 nosler as well. I started seeing different rifles having the same basic poi shift patterns and when I dryfire from the bench I can see the crosshairs jumping in the same pattern with the same consistency. I use an Accu wedge in everything except my rat tat tats but it does basically nothing for the front slop. If I grab the mag well and push over on the upper with my thumb to bind the two together the cross hair jump goes away upon dry firing.
 
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Maybe you could test your theory by using feeler gauges somehow to take up the gaps?

I see the same movement when I dry fire and thought the same thing. I went so far as to bed a receiver set with jb weld between them. It made no difference at all that I could tell.
 
There have been times I thought this slop made a difference and times I had rifles just flat-out shoot with the slop which left me second-guessing myself. I'm guessing it probably makes a difference what kind of rest it's on and how the uppers weight is distributed and balanced. It's just hard for me to not believe that it doesn't make a difference when I can watch the dry fire crosshair shift pattern match my actual groups.
 
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Just switching from an Anderson lower to the Omni hybrid polymer is right at 1 in of p o i shift to the 10 position with the polymer. Now I suppose some of that could be primer strike difference. The polymer has a SD-E trigger and the Anderson has a Geissele national match in it. Something is definitely going on with upperg lower relationship in my opinion. I've seen this POI shift when swapping lowers on other rifles as well.
 
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While the mating between upper and lower might shift your group, it should still group. A 1:10 twist is a pretty fast twist rate on a bullet that light that goes that fast. I once had a customer request a 1:9 twist .204 because he specifically wanted to shoot 45gr bullets. It was a tack driver with those heavy bullets. Anything lighter and things opened up a bit.

You might try some heavier, 45gr bullets.
 
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