Tuning .223 AR15 Reloads for Accuracy

[257Roberts]

Started off my competitive shooting career with a Fulton Armory CMP Upper with a 1-7 Krieger. That beast was a hammer and took me to master long range. My go to load was 24.5gr H4895, LC brass and a 77gr Sierra at mag length. I would load the same recipe with 75 AMAX past mag length for long range. It was an honest 0.5MOA setup if I did my part.

Back in 2014 I built my first AR15 upper, a shorty carbine. 16" 1-7 WOA barrel with a mid length gas system. I used a Yankee Hill back-up flip front sight with gas block included, I don't think its adjustable. Need to go back and look. I've ran my old leftover reloads thru it, and accuracy is just "ho hum" 5 shots 1-1.5" at 100 yards with a 10X scope. Not terrible, but not what I had hoped for either. Occasionally can get 3 or 4 into 0.75", but there is always a flyer that will open up a total group. I'd love to use this for some short course NRA prone practice, but at 1.5MOA, I don't trust it well enough for proper feedback on a scoreable target.

I'm going to have to dig out the Zediker books again.

What are some tips you guys do to squeeze on sub MOA in your AR15/carbine platforms?
Can't really tweak seating depth for a mag length set up.
Do you tweak your charges and primers until you hit a node?

Going to be building a 6ARC once I get a barrel that's on order.
Figured Id better re-study up on AR15 loading before I tackle that one.

 

[jelenko]

A shorter barrel [i.e., 16" vs 20"] is going to have different nodes => you'll need to use a different powder charge => unless others have some good loads in a 16" AR, you'll need to do some load development.

There's also a couple things you can do to improve the inherent accuracy of an AR

Lap the upper receiver face so it mates squarely with the barrel extension​

'Bed' the barrel extension to the upper receiver with a version of loctite - many use 'blue' loctite​

Of course, install an appropriate trigger - I like the Geissele HSNM with the match rifle spring set.​

​

Is there a reason you're not considering seating bullets beyond mag length? If this is for practice for long range, that's shot with single load, yes?

 

[RegionRat]

Just curious, is that 16” WOA bbl an SPR or SDM barrel, or something else?

 

[257Roberts]

I believe my WOA barrel is the SPR version, its the non-fluted one.

No reason for mag length other than preference for this particular rifle. It could double use as a varmint rig/home defense if needed. But agreed, for practice purposes I could work up some single load rounds.

The lower has a Geissele national match trigger in it, believe the DMR version 2.5-3.5lbs.

 

[jelenko]

the DMR version 2.5-3.5lbs.

For long range you might consider using the match spring set - 1 1/2 lb first stage, 6oz second.

With 1:7, you could use a whole bunch of 80+ grain bullets with nice BC's.
Personally, I like the Berger 80.5's - fairly easy to find a good seating depth. But, take a look at what Berger, Sierra and Hornady offer in 80+ grain bullets.

 

[garandman]

For me, it was moving to 69 grain SMK's as 77s just wouldn't group better than 1.5". Hornady 68 BTHP were crap (2 MoA +) and even Berger 70 VLD's never got much better than 1.5" .... 24.7 gr CFE223 powder. Loaded on a Dillon 550C. Not really worried about temp sensitivity as this is a 0-300 yd gun.

The Sierra 69s now vary from 0.6 to 1.2" groups, @ 100 yd, using a 1-6x LPVO. I'm sure I'm losing as much as 0.5" using the LPVO.

This with a 14.5" bbl p&w flash setup.

 

[garandman]

For long range you might consider using the match spring set - 1 1/2 lb first stage, 6oz second.

With 1:7, you could use a whole bunch of 80+ grain bullets with nice BC's.
Personally, I like the Berger 80.5's - fairly easy to find a good seating depth. But, take a look at what Berger, Sierra and Hornady offer in 80+ grain bullets.

I'm not fitting many 80+ gr boolits into AR mags. I've got Berger 80.5's I shoot in 224V. . No go in the AR, Gotta seat too near / below the ogive, and then I don't like the neck tension. Never shot 'em, I just don't like the set up, for crimping or really at all.

See Disclaimer (below)

 

[Ned Ludd]

Can't really tweak seating depth for a mag length set up.

Actually, you can. Pick the longest COAL (seating depth) possible for the bullet you're using that will allow the loaded rounds to feed reliably from your mags. Use that as your baseline/zero and test the bullets seated incrementally farther into the case (i.e. increasing jump). Chances are good that you can find a seating depth optimum using this approach, which can potentially make a world of difference in the precision. If you have to move the bullet more than .040" or .050" farther off the lands to find the sweet spot, it may also be necessary to back off the charge weight a few tenths grain to maintain velocity as the effective case volume diminishes and pressure increases. Also, it may be beneficial to test in larger (more coarse) increments first, just looking for a seating depth region that shoots better than anywhere else. You can then re-test over that region in smaller increments, if necessary.

IMO - optimizing seating depth is possibly the best tool we have to tighten groups. I wouldn't forego that process and use only a preset mag-length COAL if the precision at a standard COAL was unacceptable, especially when it may well be possible to improve the precision by adjusting seating depth in a single direction farther from the lands (i.e. jump). Berger Bullets has a bulletin regarding a fairly coarse preliminary method for optimizing seating depth for VLD bullets, which may sometimes be finicky, that covers a very wide seating depth range. The portion of their test that involves jumping bullets a relatively long distance may be of interest to you with regard to optimizing seating depth in a single direction. Although their intent was aimed at VLD bullets rather than at the optimizing seating depth in mag-length loading situations, parts of it are still applicable and their method can be applied to any bullet:

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

Obviously, there is a limit to how far off the lands you can reasonably seat a given bullet without giving up too much usable case capacity. Nonetheless, that limit can be pretty wide as evidenced from the seating depth test range suggested in Berger's method. So there is a good chance the seating depth for a given bullet might be tuned within that range much better than simply using a preset COAL value and hoping for the best. It's worth a try, in any event.

 

[garandman]

CAN adjust seating depth... Not sure ya SHOULD.... especially on hot loads.

 

[RegionRat]

The typical 23.5 -24 grain charge of RL-15 or Varget does not overpressure during a seating depth search in an AR service rifle with a Wylde chamber WOA or CLE bbl.

That is not to be confused for general advice to take any design and attempt to set a bullet deep, but don't be surprised to see many match gun designs actually slow down with increasing seating depth during depth ladders. It goes against the common mantra, but it happens all the time.

The leverage from seating depth in the long line loads is worth the effort. It can take half a minute off of a 600 yard group when an example might start at one MOA and goes down to less than half MOA.

The group size improvement shows up at two practical nodes, generally about 25 to 35 mils apart in the SMK 80. The nodes for the SMK 77 and TMK 77 at mag length are a little more random.

Since the TMK 77 splits the BC difference between the SMK 80 and SMK 77, some Service Rifle folks are starting to try and run it across the course with a single charge and seating depth from mag length. On some government bases we are required to run "factory" ammo so I was forced to compete with the TMK 77 at 500 and 600 at mag length and I did okay with a 199 at the long line the last time out.

We just don't have the giant database to generalize how much the groups change with depth searches at mag length, but roughly a quarter minute off at 600 yards with the 77 TMK in a WOA SR.

 

[garandman]

It just seems like if you wanna shoot 80 plus grain bullets with a high BC, Don't try and cram them into an AR15 mag... get a different gun/different caliber. I shoot 224V 85.5's from a bolt gun platform...with a 2.320 OAL.

Yeah I can shoe horn a 454 cu. in. with a super charger into a Porsche body ... but why?

 

[Pawnee Bill]

Do you anneal your cases? If not, that could help tighten your loads. Look at Johnny's Reloading Bench on Youtube, he did a lot of testing with 223.

 

[RegionRat]

It just seems like if you wanna shoot 80 plus grain bullets with a high BC, Don't try and cram them into an AR15 mag... get a different gun/different caliber.

Yeah I can shoe horn a 454 cu. in. with a super charger into a Porsche... but why?

You have a valid point, but keep in mind... not everything done with an AR happens close to the tailgate of the truck, and/or rules apply to certain games. (Not to mention the cool factor when folks put big blocks in a Porsche or VW, or Vega, etc....) (We don't feed them into a magazine, they ride on the single follower.)

1) There is a limit to what a given man/soldier/hunter can carry. If the use of long loaded ammo for certain scenarios allows one gun to play the short game and the long game at the same time, it is worth looking into.

2) High Power Competition like Service Rifle has a long line stage for 600 yards and it is common to load longer than mag length for that stage. You leave an advantage on the table if you try and run it with magazine length ammo. You also leave an advantage on the table during the other short line stages if you only bring a gun optimized for just that long line stage and handicaps itself in offhand, sitting rapid, and prone rapid. All SR XTC guns are a compromise.

3) In a forum, we have to keep an open mind and remember that none of us speak for all of us, nor does everyone share the same interest in participating in every game.

It is always okay to keep a discussion wide open and civil. It wrecks the forum if we get narrow minded or attack each other for an interest we don't personally understand or share.

It is okay to help a poster with an interest in something we don't agree with, it isn't okay if we derail him or belittle his goal unless what we are doing is steering him from harming himself.

The poster asked the following:
What are some tips you guys do to squeeze on sub MOA in your AR15/carbine platforms?
Can't really tweak seating depth for a mag length set up.

Along with load development and starting with a higher quality upper, one way to get sub MOA is to try bullets that don't fit in the magazine when accuracy shots are required. A carbine isn't generally an accuracy tool, it is for long humps and short range and kicking doors.

That said, rigs built with WOA bbls have in fact performed well under 1 MOA when the ammo and the driver know what to do. You wouldn't call that a typical carbine, but it is 16".

We are also trying to point out the assumption in his second statement isn't true, we can in fact adjust at or below mag length to get better performance and still keep reliable function.

As always, YMMV

 

[garandman]

As always, YMMV

I have no desire / intent to suggest what others should do with their firearm of choice.

I just believe 80+ grain in an AR 15 platform will never be as capable as the same bullet in a different platform better designed for it.... that allows the shooter more than 2.276 max OAL. I've tried it. Its always gonna be "off." And do less than it would in the "right" gun. So * I * wouldnt't do it myself.

By explaining that and my rationale why, I simply hope to give the reader food for thought. Then if he still wants to cram that blown 454 into the Porsches body.... its his / her money.

 

[skeeljc]

Have someone make a custom barrel extension that can be shrink fitted to the upper receiver like JP Rifles does.

 

[dnellans]

Have someone make a custom barrel extension that can be shrink fitted to the upper receiver like JP Rifles does.

tell me more…

 

[lawman29]

Don't forget to test different primers.

 

[skeeljc]

tell me more…

Watch JP's video explaining how to assemble their "Thermo Fit" uppers. Here is a link:

JP Thermo Fit

 

[miningshawn]

My best luck with the AR platform in 1:7 or 1:8 twists has come from 73 grain Bergers, or 77 grain Bergers. 69SMK have given me good results, but not as easily as Berger.

Small tips for the AR:
1.) Bed the barrel extension in Loctite.
2.) Accu Wedges cannot hurt and occasionly help.
3.) Before installing the barrel polish the feed ramps, Flitz and a Dremel work well with a .30 cal bore mop.
4.) Align the gas tube, plenty of spots on the internet explain this.
5.) Adjustable gas blocks are super nice, especially when they are clamp on instead of using the barrel for support.
6.) Most magazines will allow 2.265 - start there. That leaves 0.040 for seating depth tuning.
7.) If an optic is used, bed it.

Just a few tips.

 

[LVLAaron]

These are 5 shot groups from my AR15 "competition" rifle.


The first things I do to the rifle to make sure it's a shooter:
1. Bed the barrel to the upper.
2. Adjust the gas. I adjust it a little "hot"
3. Single feed. I can take the same load pictured, mag feed, and get very different results. Drop the bolt on every round. Accuracy is about repeatability. Mag feeding is not consistent.
4. Related- always load the bipod the exact same way. Many ways to load... No load, heavy load. Pick a method and commit.
5. Check your pin protrusion
6. KEEP IT CLEAN. KEEP IT LUBED. AR's are dirty guns. Clean the bolt carrier assembly after every range trip. Make sure the pin travels freely. The pin easily gets gunked up and consistent ignition matters. You're using it as a precision rifle, not an AR. Run it like a precision rifle.
7. Check, and correct if needed, the bolt lug contact. AR's have a lot of lugs. Easy to 2-3 of them to be out of true.
8. True the upper receiver face.
9. Use a WOA or BAT Machine shrink fit barrel extension


About the ammo
1. Sort bullets. Don't get wrapped around the axle thinking about it. I just pick one method and sort. Might be OAL, might be base to ogive.. Just pick one to cull the obvious bad ones out. Just measure something and be ready to use 5-10 percent of "off the shelf" bullets as foulers or sighters.
2. Use a neck mandrel to expand your necks. This probably made the biggest difference in 223 I've ever found.
3. Use a stick powder
4. Use a magnum primer.
5. Keep in mind your lot to lot variances. Commercial bullets can vary by as much as 20 thou from box to box...

A dozen other little things I do to the rifle to make sure things are how I want them....