Help with AR accuracy in 223

[Viperdoc]

I have been posting in the reloading forum and looking for help in improving the accuracy of my AR in 223, built with a Krieger 1/9 26" barrel. At best, I can get around 1" groups (five shot at least), but never consistently better. Would like to see groups in the 3/8 range, shooting with a match Geissele trigger, 8-32 scope, and off a heavy rest with rear sandbag.

Have really beat on the reload aspect, new Lapua brass, CCI BR primers, Sierra 69MK bullets. Brass were FL resized, opened with a mandrel, neck turned, resized, trimmed and chamfered, and then loaded. Neck tension is 0.003. TIR ranges around 0.002-0.003 at the ogive, using Redding competition seating die. Best SD I have seen so far is around 19 (ten shots), using Varget.

Perhaps Varget is too slow a powder for the 69's- my rifle seems to like AA2520, TAC, and H335 better, but even then, it is hard to consistently get better than around 3/4 inch consistently.

Running out of ideas on improving accuracy, but still think the rifle is capable of much more. It tends to shoot much tighter groups with lighter bullets, like match bullets in the 55grain range, and I have not tried any of the heavier bullets, like the Hornady or Bergers at around 77 gr.

Still, would like to find a good combination using the Sierra 69MK bullets, if possible.

Any other ideas or things I might be missing?

 

[6BRLongRange]

Try RL15 and Wolfe or Winchester primers.

 

[fivering]

Try seating the 69's out far enough so they just feed dependably out of a magazine, use 23.5 gr H-2895, Wolf Small Rifle Magnum primer, (the regulars are too soft), be sure to use one of the rubber Accu-Wedges, and you should get what accuracy the barrel is capable of.

 

[Viperdoc]

So far I've gotten input to try Reloder 15, a VV powder, and now more. Other than randomly trying these, is there some logic to making these choices? So far I've tried H335, AA2520, Varget, and TAC.

It seems that H335 and TAC are a little better, then AA2520, and finally Varget, despite what some have written. Does this suggest that perhaps faster powders work better with the Sierra 69 MK's in my gun? Should I then concentrate on trying some different powders in the same burn speed range?

 

[6BRLongRange]

Most HP shooters tend to use RL 15 and Varget with 69-80 gr bullets. 24.0 gr is kind of a provenoad behind 69_77 grs

 

[rcw3]

Viperdoc

There are a lot of places to look for accuracy issues with an AR-15, some you have control over, some you do not (i.e. like if you have a so so barrel that just will never shoot well, there's not much you can do with that other than to replace it, and Krieger barrels are not immune from that either, and it can happen with a Krieger although they make great barrels).

First place I would start is on the loads you shoot. Straight away, I would say the 69 gr Sierra does not always shoot well in all barrels and I have seen barrels that like them and those that don't.

If I were looking to get an accurate starting load off the bench with an AR-15, I would start with a bullet like the Sierra 52 gr BTHP bullet as it is light and has a somewhat blunt front end and with the right load will typically shoot well in just about anything that can be made to shoot well (i.e. it's my "go to" bullet for .223 AR's that may have an accuracy issue and I need to find out if it's a load or loading issue or something else.

We don't know what your chamber design and free bore is, but over the years I have found that a blunt little cylindrical bullet like the Sierra 52's shoots well in just about anything, and if a 223 won't shoot that, then there's something else wrong with it. I cannot say that for the 69's.

Next I would try a powder like IMR 4895 or H4895 because they are good powders for lighter bullets and have a burn rate and pressure curve that is good for an accuracy load with a lighter bullet in an AR-15 (they are "go to" powders for me when I have an AR with an accuracy issue) You can use H335 in a pinch as well. Around 24 - 25 gr seems to work well (start at 24 gr). Varget and RL 15 are slower powders and are typically great and used typically for the bullets in the 70-82 gr range, but when you are down in the smaller bullets a little faster powder is better for accuracy testing (i.e. to see if it's a load problem or a mechanical problem).

For an AR-15, you're wasting your time doing neck turning and getting all crazy with brass prep - for gosh sakes, it's a battle rifle conversion we're talking about here - it's never going to consistently shoot in the 1's or 2's, but groups in the 1/3" to 1/2" is workable (usually .5" MOA is realistic with most).

Remember an AR-15 was never a bench rifle and it was not designed as such. As a semi auto, it tends to jump and twist before the bullet gets out of the bore and the heavier the bullet you use with slower powders that push more gas out the muzzle, the more that's a potential issue (i.e. you noted you felt it shot better with lighter bullets). For shooting off the bench with AR's if you are working for the most ease of accurate shooting I would favor smaller lighter bullets and faster powders. Also, if you are shooting an AR using a very light hold or free recoil technique I have not found that to work well, except with things like the 20 cal uppers where there is almost no recoil to start with. Also, since it's a push pin rifle with aluminum upper and lower receivers using a hard cheek pressure is sure to kill accuracy. You may want to check out this page:
http://www.6mmar.com/Benchrest_AR.html

Good luck!

Robert Whitley
www.6mmAR.com

 

[fdshuster]

Viperdoc: In addition to all of the above suggestions, and based on an article in the October 2001 edition of "Precision Shooting", by M.L.McPherson: "Best groups fired from this Bushmaster Varmint model required careful front bag positioning so that the receiver and magazine would just almost touch the front rest". I'm not able to use my Sinclair front rest with the AR's because of their design, but get excellent results with a hard packed bunny eared front bag. Tried bag at front of handguard, then midway back, and finally, as suggested by McPherson, with the bag almost touching the front of the receiver, and for me it worked. Groups were measureably smaller. The "flat" forend and buttstock adapters also have to be an advantage, and of course, make sure the rear sling loop is not contacting the rear bag. I remove mine for bench work. A rifle that was never designed for benchrest use, but with a little work and ingenuity they can be made to shoot, as two of my Krieger barreled uppers have proven.

 

[6BRLongRange]

Now that there's a class for ARs in IBS things will become more bench oriented in the future. Look at the bag riders available if you want the best accuracy possible and be prepared to experiment. 75 Hornady seem to shoot good in some cases also. Buy a box of them, 77 SMK , and any others you're interested in 2-3 lbs of powders and plan on spending a day at the range. 52-55 GR flatbase bullets will shine at 300 yds and under.

 

[Walt_NC]

FWIW, this load has consistently turned out sub 1/4" groups for me from an 18.5" Noveske barrel:

77 gr SMK w/ cannelure
24 gr IMR 4895
CCI 400 primer
Winchester brass - the bulk stuff sold at Walmart

I use a full-length Hornady resizing die, trim the case to 1.750", chamfer and deburr, uniform the primer pocket and deburr the flash hole. I don't mess around with neck turning.

 

[buckbrush]

FWIW,

I am shooting 25.5 gr of Varget with the 69 SMK's. Groups at 100 yds consistently were at right about an inch or a little more. However, at 300 yards they are consistently under 2" off of bipods and rear bag. I have read about bullets "settling down" at longer ranges when they are long sleek high BC types. I have two other guns that are like this.

This is a factory DPMS 24" varmint gun.

 

[cmillard]

no matter how much attention to detail i had on my ar-15 "match" loads, i could not get single digit sd. i think the lowest i ever got was 13 fps sd. it is hard to attain and a waist of time in the ar platform. as mentioned above, the best accuracy i ever had from a 9" twist barrel was from the 52 grain MHP. That bullet just plain shoots!! yes, the 69 grain bullets work better with the faster burn rate powders as mentioned above. it sounds like you have some good components on your rifle, but what is the rifle's intended purpose? some other things you might want to try, as i have with great luck, is adding a hydraulic buffer and get a bolt carrier weight.

 

[fdshuster]

buckbrush: Your load of 25.5 of Varget with the Sierra 69 gr. #1380 has been my standard accuracy load for my 9 twist and faster 223 barrels, AR's, bolt's and a single shot. That load just plain shoots!

 

[Viperdoc]

All great advice, and thanks for the ideas. My AR in fact does have a heavy BCG, and a bolt carrier weight, and hydraulic buffer. I have been working with Varget and the Sierra 69 MK, but the best it will shoot is around an inch or a little over. I can get the Sierra 53 MK to shoot at around 1/2 inch (with Tac or H335) in the same gun, using the same hold and rest. Did just get a flat bag rider and anxious to try this to see if it helps. (I have one of Mr. Whitley's bag riders on my space gun- I assume it's the same person, and it is a great addition- finely machined and finished, with great attention to detail. Unfortunately it does not fit on my AR free float tube, which has a fixed Picatinny bottom rail, but still works great on my 6.5 space gun. Thank you.)

I have heard that some bullets seem to do better at longer ranges, as mentioned- is this a characteristic of the bullet itself, or some combination of bullet/barrel? Yet, others report similar combinations, and great results. I would have expected the Sierra 69MK's to be stabilized by 100yds, but perhaps what I'm seeing is "normal" behavior?

Took a step back last night per Mr. Whitley's advice and loaded around 40 each loads of 53 Sierra MK with H335, and Berger 62 also with H335. All other variables were the same: new Lapua brass, CCI BR primers, all cases run with OS mandrel, then full length resized with 0.246 bushing, trimmed and chamfered on Giraud. Gave neck tension of 0.003, and most rounds with bullet runout of less than 0.001. This was consistently less than what I was seeing with the Sierra 69MK's, which frequently would give a RO of 0.003 or more, using the same seating die. Again, is this a bullet characteristic, or perhaps some way it seats in contact with the seating die?

Will be loading some Sierra 77's this AM with Varget, and hopefully off to the range this afternoon with the chrono.

 

[cmillard]

viperdoc, if you plan on shooting the 77s, give aa2520 a try versus Varget. although i love varget, you will get some more speed with the 2520, and with a 9" twist, you will need that extra speed for the 77s. i gave up trying to get the last little bit of accuracy possible out of my long range ar. i've settled on the fact that it shoots 1" 10-15 shot groups at 100 yards and i've tried to best that to no avail. but, i have had some really impressive groups at 891 yards with that rifle shooting 77 sierras out of the 7" twist 18" douglas barrel.

 

[fordwrench]

I have an armalite 1in 8 twist that will shoot 1s and 2s with 52s 69 and 75s. Try benchmark with the light bullets n540 w the 69s and rl 15 w the 75bthp match hornadys. Regular forester fl die br seater. Prepped win brass and cci primers. Try not using the mandrel and turning necks. These are at mag length also. Goodluck !

 

[Viperdoc]

I posted a reply on the reloading forum regarding my results today with my AR reloads. Rather than cross post, please check it out- I was very lucky today.

 

[Albert E]

I have 3 bolt guns with 24" Shilen barrels in 223 Rem chamber with 1-8 twist. Heavier bullets would not group as well as 55gr Sierra Blitz king with 24.5 gr Benchmark. After getting .023 results for 5 shots. I went on to try this load in 2 AR's I built with 24" barrels.....they shoot like the bolt guns with this load.

 

[NZ_Fclass]

My experience with AR's is a litlle limited, due to our wonderful Prime Minister....but I did do some testing with bullet length/seating, before it had to go. My pre-fit DPMS heavy barrel was far too long in the chamber for mag length loads so I had it re-chambered to suit 69g Lapua seated to mag length. Bullet was set to 20 thou jump. Groups came in and shot under .5MoA. Load was 25.4Varget/CCI BR/ ADI brass. IMR 8208 is also a great 223 powder.

 

[Jeff Porter]

69 SMK- Wylde chamber 1:7 twist. 24.0gr H4895 2.240” OAL.

100 yards and 500 yards. Two different AR’s. 100 yards was a 26” space gun , 500 is a 20” service rifle Both from a sling on the ground. Shooting an AR from a bench or bipods is an art. It is not the same as a bolt gun.

These do not need to be jammed as they are stubbier than a 77 or 80 anyway. 2.260” May be in the lands in a Wylde and will be in a standard 223 chamber. 11.2 SD in the e target is about as good as it gets for me with a 223 gas gun.

 

[AWS]

One thing you might want to check your gas block. I have a high end AR and the gas block would just touch the hand guard when it was on the rest. I ended up shimming the hadguard and things improved.