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Lapua brass for AR15

Try some 69 or 77 SMK’s with LC brass and 23-24 grains of 8208 xbr.
Run adequate neck tension for a gasser as well.

Also make sure you’re gas tube isn’t battling the gas key on bolt carrier.

I have some 69g smks I can try. What neck tension should I be doing? I think it's at .003 right now. And I have no idea about the gas tube or gas key. I'll have to you tube that. It's a 20" heavy barrel 7.7 twist. Should have no issues with 50-80g bullets. Brass I'm using is the 1x fired stuff from DDranch here. It's been FL sized and gives about .003"-.004" bump in my chamber.

Main use of the rifle will just be a steel banger out to 800 and the occasional coyotes. So it does need to shoot under MOA consistently for me to have any kind of faith and confidence in it. Otherwise I'm just wasting time and money with it.
 
3 thou is a bit on the the light side for a gasser.
Lot of videos to see if gas tube is copacetic with the gas key.
Also try Xterminator with the 55’s and other light bullets.
55 ballistic tips generally shoot well.
 
The first 2 targets were the 1st time out with a powder charge work up. Both Benchmark and 8208 were used with both bullets. The corresponding targets show the top accuracy loads for that day. The 3rd target was my 2nd time out. Took the 53g vmax/Benchmark load out, along with some factory frontier 55g fmj (which were waaaaaay over pressure in this rifle) to zero the new strike eagle, and also try some factory federal 53g vmax just to see how they'd shoot. I figured the 53 vmax/Benchmark would easily do 5 under MOA since it did 3 at 1/2 previously. I would assume the gas block/key is ok since I bought the upper from a gentlemen who used it at camp perry for a couple matches. He was able to get 1/2-3/4 MOA pretty easy from it, and that's with a 4x scope and a heavier trigger.

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I've read quite a bit on both sides of the primers. I'm just using up the last 5-600 of my 400s leftover from my 222. Then I'll use either 450s or BR4s. The 7.5s are for my LR bolt 223 wylde.

Could that be part of my issue with consistent accuracy? I remember using some of the 400s in a bolt ruger target 223 I had for years also and had no problems with consistent 3/8-1/2 MOA from it.
 
Is it worth it to use Lapua brass in a precision minded build AR15 223? I was thinking about trying some of it in my AR. I'm just using some 1x fired, all same headstamp, ready to go range brass right now and not super impressed with the accuracy. Could also be that this is my first AR coming from bolts all my life. They are definitely different, and not quite sure how I still feel about them. I'm willing to give it a good go though before I decide to either keep it, or send it down the road...
A few other things to check before chasing loads that haven't been discussed.

Is the handguard free floated? Remove and inspect.
Does it have a flash hider and is it tight if so? Possibly needing a new crush washer?
Single stage or 2 stage trigger? What weight? Trigger clean and smooth?
Inexpensive scope mounts and/or scope can be a killer for an accurate rifle. Do a BOX test?
Adequate shoulder bump (another reason not to waste expensive brass) and neck tension?
Someone mentioned carrier hitting the gas tube?
Bolt and carrier cleaned and lubed properly? Carrier needs to open up and return to battery EXACTLY the same each firing.
Lastly, a fired AR is opening the bolt before the bullet is leaving the barrel. It's so important to follow thru with the shot and remain in the sights/scope till the bullet is on target.
 
Thanks everyone. Ill just stick with what I have and do some more testing. I'm looking for 1/2-3/4 MOA from it for 3 shots at the minimum, which it should have no issues doing. Aero lower, WOA/Krieger upper, Luth MBA-1 stock, Larue MBT trigger, Warne 34mm cantilever mount with a Vortex 5-25x strike eagle.

First outing I tried 53g vmax and 73g ELDMs with 8208XBR and got some 1/2" 3 shot groups at 100 yards, never to be repeated again... Same loads shot 1.25-1.5" at 100 the next time out for 5 shots. Factory federal 53g vmax did 1.25-1.5" at 100 yards for 5 shots. That's just not acceptable for me or the rifle. Maybe from a cheap Walmart AR with factory ammo, but not a quality AR with handloads.

Most of it is probably me. I'm just not an AR guy and haven't figured out how to shoot them accurately. I mean from a bench, I'm doing everything the same as I would with my bolts. My bolt 223 will shoot in the .2s and .3s at 100. So what gives?
First get you a good adjustable gas block, this will save wear & tear on your brass of any kind. Next, get some AR-Comp and a box of Berger 77 gr. OTM. Do a good ladder test, you should find a sweet spot around the 22 gr mark. If your gun will shoot, you will find the right combo for your MOA requirements. I have not had any luck with Hornady bullets.
 
A few other things to check before chasing loads that haven't been discussed.

Is the handguard free floated? Remove and inspect.
Does it have a flash hider and is it tight if so? Possibly needing a new crush washer?
Single stage or 2 stage trigger? What weight? Trigger clean and smooth?
Inexpensive scope mounts and/or scope can be a killer for an accurate rifle. Do a BOX test?
Adequate shoulder bump (another reason not to waste expensive brass) and neck tension?
Someone mentioned carrier hitting the gas tube?
Bolt and carrier cleaned and lubed properly? Carrier needs to open up and return to battery EXACTLY the same each firing.
Lastly, a fired AR is opening the bolt before the bullet is leaving the barrel. It's so important to follow thru with the shot and remain in the sights/scope till the bullet is on target.

I'll try to answer all your questions here. I'm almost positive the handguard is free floated from the factory. There is no flash hider. Trigger is a LaRue 2 stage, it breaks about 2#. Scope is a Vortex strike eagle 5-25x in a Warne cantilever mount. Have not done a box test, and come to think of it, never have in my 30 years of shooting. Shoulder bump is around 3-4 thou, neck tension is around 3 thou. Rifle has been cleaned and lubed within 100 rounds. How often should they be cleaned?

I'm not looking to buy more or different components. I have plenty of Benchmark, IMR4895, and 8208XBR. Along with plenty of Hornady, Sierra, and Nosler bullets. If it won't shoot with those components, than I don't want it if it's going to be that picky.

Maybe it will shoot better after the brass has been fireformed to my chamber?

I'll go through all the specs again on bump and tension also. Make sure everything is tight on the rifle/scope/mount. Re run a few bullet/powder tests again at 100 yards from a bench, front rest/rear bag. 3 or 5 shot groups? What are some of your guys accuracy expectations from ARs with a similar build?
 
I'm using an RCBS FL die set. No crimp on the bullets. Read a lot of info regarding crimping. I'm on the side I don't feel it's neccesary, as long as the bullets aren't moving during recoil. I see no need to crimp.

I'll get back with the exact sized, loaded, fired specs on the brass.
 
I'm using an RCBS FL die set. No crimp on the bullets. Read a lot of info regarding crimping. I'm on the side I don't feel it's neccesary, as long as the bullets aren't moving during recoil. I see no need to crimp.

I'll get back with the exact sized, loaded, fired specs on the brass.
The Lyman M die mentioned above is just for expanding the neck just a little to accept the bullet without chamfering or deburr the neck when loading. The Lee Factory crimp just merges the non- chamfer neck to the bullet after seating. This process saves a lot of hand work and that work is done by just using your press.
 
69 SMK with 23.8 8208 loaded to 2.240” OAL shot well in about any AR I have had with a Wylde chamber ( and that is a large number of barrels ).

1/2”-3/4” groups for three shot.
As mentioned harder to shoot an AR from a bench than it should be. Takes a leaning curve. I could shoot same size groups from a sling as from the bench.

3-4 thou neck tension and bump worked too. Check by letting the bolt drop and strip a round from the mag and then extract and measure it. If not enough neck tension it will “grow” due to the inertia of the violent BCG slamming it home.
 
A few other things to check before chasing loads that haven't been discussed.

Is the handguard free floated? Remove and inspect.
Does it have a flash hider and is it tight if so? Possibly needing a new crush washer?
Single stage or 2 stage trigger? What weight? Trigger clean and smooth?
Inexpensive scope mounts and/or scope can be a killer for an accurate rifle. Do a BOX test?
Adequate shoulder bump (another reason not to waste expensive brass) and neck tension?
Someone mentioned carrier hitting the gas tube?
Bolt and carrier cleaned and lubed properly? Carrier needs to open up and return to battery EXACTLY the same each firing.
Lastly, a fired AR is opening the bolt before the bullet is leaving the barrel. It's so important to follow thru with the shot and remain in the sights/scope till the bullet is on target.
That last sentence is a falsehood that a lot of people believe. The bullet has to pass the gas port before gas is allowed to enter the gas port, by the time the gas reaches the bolt carrier and it begins to move, the bullet is already out of the barrel. If this were true, there would be a whole lot of gas being directed back toward the shooter, enough so that safety would be a major issue. The brass would be destroyed by the pressure. Neither happens. AR's have withstood some really extreme loads, far beyond what is considered safe to use. One guy I know put 30gr of Ball C behind an 80gr Sierra and the gun survived. How he managed to get that much powder in the case is beyond me! He forgot to put his reading glasses on when he was loading his ammo. In that instance, maybe the bolt was starting to unlock but, obviously wasn't fully unlocked or he wouldn't have had a face left.
 
First thoughts always go to “what changed between trips to the range”.

You said it was once fired range brass. Did you buy it processed, or did you clean and size it? If it was clean, did you resize it? Were you shooting brass fired in your chamber the second time?

Could be as simple as squeaky clean brass and necks with some carbon inside. Less friction.

Other than cleaning the barrel, was anything else apart and back together?

Something good to check after the first time shooting is barrel nut torque. First time heating and cooling can cause them to loosen up if they were assembled at the low end of the torque spec to align the gas tube.

It was mentioned to check for bullet movement after chambering, it’s also a good idea to check rounds in the magazine for bullet set back from banging around in the magazine under recoil.

Check scope movement and preload in the rail mount. More so if it was off between trips.

Lots of little things, but look for changes between trips.
 
I could shoot same size groups from a sling as from the bench.
I've found the same.

In experimenting with bench techniques, I've found using a 'bag rider friendly' buttstock helped a lot.
I was told and found to be correct is to ensure the front rest is close to the receiver and in exactly the same position for each shot.
 

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