Rem .223 AR15 trying to reduce total indicated runout

[dsbur]

Having issues with trying to reduce total indicated runout on my AR loads. I have repeated several times on paper that loads with TIR less than .001 (measured with the Sinclair tool https://www.sinclairintl.com/reload...s/sinclair-concentricity-gauge-prod37479.aspx) will shoot in the 1/3MOA range at 200yds. Took me about 400rds to figure out how to do it consistently (ugh...)

Only about 25% of my reloads meet the <.001 TIR criteria, I need to reduce the culls.

Shooting as I do F/TR style with a Duplin bipod and heavy bag in back, prone. This is an Armalite National Match rifle with a Hvy 20"bbl freefloat, J+P handguard in 5.56 1x8", stock lower (weight in stock) with a rear stock slider and a flat top A3 upper and 6-24PST Vortex scope on risers.

Looking for the missing link on what I am doing wrong reloading-wise to reduce TIR. Here's what I do...

1. Using Black Hills Match brass, or military IMI (same lot) or Lake City (same lot). Neck thickness' .012 non-turned.
2. clean primer pocket, ultrasonic clean.
3. AMP Annealer after every reload as per the AMP guidelines for timer set for each different manufacture.
4. RCBS single stage press, resize with Redding FL die .223 5T with .001-.002bump. No expander spud. Imperial lube.
5. SInclair expander mandrel E22 (https://www.sinclairintl.com/reload...air-expander-mandrel-oversized-prod33134.aspx) polished with 2000 wet and using Imperial on the inside of the neck. Gives me about .002 measured tension.
6. Trim, outside chamfer RCBS tool, inside chamfer K&M tool (http://kmshooting.com/case-neck-chamfer/large-6mm-338-controlled-depth-tapered-reamer.html).
7. Clean inside neck, re-lube lightly with Imperial
8. Prime CCI BR4's, 23.3gr H4895 weighed with RCBS Chargemaster trickled up by hand.
9. Seat Nosler CC 77gr with Redding micrometer seating die ST 5U with an inside polished seating head (Iosso on a Q-tip and drill). Magazine length.

Things that I have noticed-
1. Fired cases neck measure near perfectly concentric
2. Am cleaning dies and seating head more than usual, not over-lubing with Imperial
3. I use a similar routine for my .308 F/TR and don't have anywhere near the TIR issues.

Other than A) switching to maybe a Whidden die set or B) trying Lapua brass I can't help but think there is some minor detail I am missing. I've read about every TIR thread here, have been using the o-ring trick on all (indexed ) dies, tried turning cases during sizing and seating, inspected/measured shellholders. Up for suggestions. Apologies in advance for all the longwinded details-thanks in advance...

 

[jepp2]

I have repeated several times on paper that loads with TIR less than .001

Most folks with a lot more knowledge than I have, say that if your TIR is 0.001" or 0.005" they all go in the same hole. While I strive for the straightest loads also, I recognize it may not pay benefits.

What is the TIR of your case necks after sizing?
What is the TIR range of your loads, and where on the bullet are you measuring the runout?

 

[Richard Coody]

fired brass should be the best it will ever be concentricity wise.

1. turn your necks on all your brass to a uniform thickness. you will need one of these to measure your necks. you might be suprised how bad they are. That variation in brass thickness my be a good part of the runout you are measuring. i know it was for me. fired brass and bushing sized brass have all that variation on the inside. that is why i chuckle when i read.about the low runout some.shooter has that uses a bushing die. that variation certainly effects neck tension.
http://kmshooting.com/mitutoyo-micrometer.html

2. check concentricity after sizing. if you find that is when the problem occurs then it is either your die or press.

3. if the problem occurs at bullet seating then buy a wilson die and arbor press.

just one suggestion. quit using the ultrasonic. i did. leave the carbon in the necks. just tumble in corn cobb media. after 10 or so firings i use my ultrasonic to clean the inside of the cases.

if you insist on using the ultrasonic then by all means get imperial dry neck lube and.use it for sizing and bullet seating. seating bullets in those super clean cases plays havoc with neck tension.

 

[dsbur]

What is the TIR of your case necks after sizing? Usually around .0005 or less before I use the expander, then up to .0015 afterwards. Don't know how to get around using an expander unless I hone out my die like for my .308. Did switch to dry lube to see if there might be any improvement, was smoother but nothing noticable run-out wise.
What is the TIR range of your loads, .0005 up to .005 and where on the bullet are you measuring the runout? At the midpoint of the exposed bullet.
1. turn your necks on all your brass to a uniform thickness. I do that on my regular .308 F/TR rig but am a little hesitant for a gas gun. Starting to sound like an idea to try.
2. check concentricity after sizing. if you find that is when the problem occurs then it is either your die or press. I just sized a small batch of brass as above, set aside the cases that had near perfect runout on the (unturned) necks in hopes that the seated bullet would be truer also. Not the case by a long shot. And sized cases that had .002 runout at the neck would show near zero runout on a seated bullet.

I am thinking that brass flows really aggressively on this little gas gun. The statement that the error is on the inside of the neck is making sense (which I tried to negate with the Sinclair expander).

I am unfamiliar with neck turning for a gas gun but will do some searches.

I am culling cases that have damaged rims (that don't turn in the shellholders smoothly).

I am setting aside rounds that had even the slightest 'crunch' of powder during bullet seating.

Our club has a reloading room with a few other presses I can try.

Unfortunately it seems certain that run-out on this particular rig is more critical.

 

[Fast14riot]

A Lee collet neck die helped me get more concentric ammo. I body size and shoulder bump, then neck size with the collet die then seat in a Wilson die with arbor press. That is for my bolt guns. I'm not sure if the violent action of feeding in a gas gun might affect run out on the bullet, though.

 

[Richard Coody]

i use the k&m expander kit on my bench guns. great way to control neck tension. reason runout increased after using it is you moved the imperfections in the necks to the outside. now you can deal with them. you don't have to turn the whole neck. just clean them up. maybe 60%. obviously you have the tools. measure your neck thickness and see just how bad it is

i have had some very accurate AR's. best was a 6mm AR turbo. that rifle would shoot bugholes. got away from them because they are so hard on brass. with my bench guns brass prep is one of the most important steps. i baby that brass. putting a little velcro or pipe insulation pad on the shell deflector helps.

might try weigh sorting your brass too. i do.

after you get you neck thickness and neck tension dialed in a honed forster die might work really well for you. obviously there are inconsistencies in sizing and seating for you. cleaning up those necks might help a lot of that.

 

[dminn1]

You may want to look at your Redding full length sizing die. I used the same die with the carbide expander for my service rifle reloading duties for several years. This particular die gave excellent concentricity until I screwed it up with a stuck case. I ordered the same die from Midway and upon setting it up and running the first batch of brass discovered runout at .004 and greater. I suspected the expander mandrel might be causing the issue so I removed it and still had .004 runout. A quick call to Midway and a new die was shipped out that gave runout in the .002 -.003 range with or without the expander.

While all of these problems were going on with the Redding die I decided to order a Forester benchrest full length sizer. To say I was impressed with the quality of the ammo this die produced would be an understatement. This die made extremely straight ammo with runout at .001 or less. I ran it with the expander mandrel in place and with my Winchester brass with turned necks it gave me .002 neck tension without excessively sizing the neck. Forester offers a custom neck honing service if you are looking for a particular neck tension with a particular neck thickness.

I eventually got the stuck case removed from my original Redding die and I now have two full length sizing setups that give me .001 runout. I would consider trying another full length die based on my experience with the 3 Redding full length dies I have used.

 

[akajun]

Do this, take one of your carefully sized and prepared cases, then load it however you like into your ar
Then extract it and measure the Runout.
All semis do is turn the bullet into a bananna, however they miraculously still shoot very well.

 

[Shynloco]

Good Morning Guys,
Just logged on and caught this thread. My first question to the OP (dsbur) is, why are you going through all the details steps in GAS GUN ammo prepping, that you'd employ in a precision Benchrest Rifle? A GAS GUN is NEVER gonna shoot as accurately as a Benchrest Rifle! And your brass is ALWAYS gonna have it's BEST concentricity because (I'd hope) your chamber is perfectly round no matter Gas Gun or BR bolt gun. I have an STT AR15 custom competition built (having mostly JP Precision parts and a Geissle trigger) and it shoots incredibly tight groups using 55 - 77gr bullets @ 100 yds. But it still can't hold water to any of my BR bolt guns. I guess it's a challenge trying to achieve the impossible, but still, I wouldn't waste my time with concentricity in a GAS GUN because a GAS GUN doesn't respect the casings or ammo your shoot in them. Sure some ammo shoots better than others, but even the best take a beating. That's why I never use Lapua brass in any of my Gas Guns and rather use LC Brass that can take a beating, plus the Lapua in a Gas Gun, won't get you any better score than the LC brass does in a GAS GUN. I've tested both brass and then some. Just my .02 worth.

Alex

 

[chkunz]

Good Morning Guys,
Just logged on and caught this thread. My first question to the OP (dsbur) is, why are you going through all the details steps in GAS GUN ammo prepping, that you'd employ in a precision Benchrest Rifle? A GAS GUN is NEVER gonna shoot as accurately as a Benchrest Rifle! And your brass is ALWAYS gonna have it's BEST concentricity because (I'd hope) your chamber is perfectly round no matter Gas Gun or BR bolt gun. I have an STT AR15 custom competition built (having mostly JP Precision parts and a Geissle trigger) and it shoots incredibly tight groups using 55 - 77gr bullets @ 100 yds. But it still can't hold water to any of my BR bolt guns. I guess it's a challenge trying to achieve the impossible, but still, I wouldn't waste my time with concentricity in a GAS GUN because a GAS GUN doesn't respect the casings or ammo your shoot in them. Sure some ammo shoots better than others, but even the best take a beating. That's why I never use Lapua brass in any of my Gas Guns and rather use LC Brass that can take a beating, plus the Lapua in a Gas Gun, won't get you any better score than the LC brass does in a GAS GUN. I've tested both brass and then some. Just my .02 worth.

Alex

I concur. This may be a factor in a bolt action, bench rest rifle but not in a military style semi auto like the AR or the M14. This was a fad during the 1980s and a lot of folks were selling a tool to measure TIR and there were a lot of claims being made without the analysis to back up the claims. I did some testing with the M14 at 600 yards in the 1990s where I shot twenty 600 yard matches during 1993 with one ten shot string with straight ammo and one ten shot string with crooked ammo and that gave me twenty data points (nineteen degrees of freedom in statistical terms) to analyze. I got better than a 95 percent confidence level using statistical analysis that the crooked ammo shot scores as good as the straight ammo. If you think you have data that shows an improvement in the AR I would recommend that you get someone with the skills to do statistical analysis on the data and see what the analysis says. You time will be better spent with attention to other things. Best wishes, Clyde

 

[chkunz]

A Lee collet neck die helped me get more concentric ammo. I body size and shoulder bump, then neck size with the collet die then seat in a Wilson die with arbor press. That is for my bolt guns. I'm not sure if the violent action of feeding in a gas gun might affect run out on the bullet, though.

This is an easy test to run, measure the TIR before chambering and then eject the round and measure again. I did this once on the M14, I remember being surprised the there was a significant ding near the tip of the bullet.

 

[jepp2]

I use the expander, then up to .0015 afterwards. Don't know how to get around using an expander unless I hone out my die

I get excellent TIR on my FL sized necks, but to get there I make sure my expander isn't opening up the neck more than 0.001" and I also do the following: hone die necks, set expander high so it enters the case neck just as the neck is leaving the neck portion of the die, and I use a carbide expander on a lubed neck interior (using bootleg case lube).

I use Redding Comp seating dies and was unhappy with the runout they gave. So I tried seating the bullet in 3 steps, rotating the brass 120 degrees between each step. For me it reduced runout of the bullet by more than 50% over just seating with a single stroke. Has worked on various calibers for me.

If you run the test of checking how much chambering is causing changes in TIR, I would be interested in the results. I have always wondered about that, but never checked.

 

[dstoenner]

For absolute certainty Lake City brass needs to have the necks cleaned up. You also didn’t mention if you deburred the flash hole. LC and IMI brass the flash hole is punched not drilled.

The post about doing multiple seatings turning in between is completely correct. The way i do it with my Redding Competition Seaters is to seat half way. Rotate 90 or so seat the rest. Then turn the bullet another 90 and bounce the loaded round 2 times. At the recommendation of another F-Class shooter I tried this routine and found my .002 or less runout category grew by another 10 to 15%.

All of this said, unless your wind calls are dead on you will have more drift once you get to 600 yards and further than even .003 runout would give you.

David

 

[Fotheringill]

Just my two cents.

I have done all that you have done with various tools and dies and found that a simple Lee Neck Collet die gave me the least runout. Under $30.

Instead of driving myself up a tree, I would invest the $30 and check results after seating in your normal fashion.

 

[dsbur]

My, so many replies, I should have stayed awake last night!
My first question to the OP (dsbur) is, why are you going through all the details steps in GAS GUN ammo prepping, that you'd employ in a precision Benchrest Rifle? No more than a challenge, and it's my background in F-class. Shooting a bughole at 200yds and .5MOA at 300yds is a bit of a rush for me.
If you think you have data that shows an improvement in the AR I would recommend that you get someone with the skills to do statistical analysis on the data and see what the analysis says. I have nothing more than about 100rds overall with TIR sorted loads, with the minimum runout loads showing a glaring improvement. Could be relevant or could be psychological. With so much bullet jump (magazine length loads) I have a hard time believing it myself.
I get excellent TIR on my FL sized necks, but to get there I make sure my expander isn't opening up the neck more than 0.001" I have access to barrel hones for my dies. My expander does seem to work at it although going back to dry lube inside the neck made a substantial improvement on friction.
This is an easy test to run, measure the TIR before chambering and then eject the round and measure again. On the docket for this afternoon at the range. I could be all washed up on this one!

 

[KevinThomas]

Using Benchrest techniques for an AR . . . what could possibly go wrong?

 

[Richard Coody]

Using Benchrest techniques for an AR . . . what could possibly go wrong?

works for me

Robert Whitley 6mm AR TURBO 40
fireformed lapua grendel brass, br4, lapua 105 scenar L jammed 0.010, 28.2 gr H4895, 2840 fps.

 

[Shynloco]

Richard,
That's completely changing the issue. The OP is shooting a .223/5.56 Armalite, NOT a custom built AR in 6mm. That is hardly comparing apples to apples.

Alex

 

[Richard Coody]

Richard,
That's completely changing the issue. The OP is shooting a .223/5.56 Armalite, NOT a custom built AR in 6mm. That is hardly comparing apples to apples.

Alex

this is a.home built .223 wild. just never could get it where i wanted it to be. quit messing with ARs. too hard on brass and it is so much easier to get the accuracy out of a bolt gun

 

[Shynloco]

Frig man!!!! Those are some awesome groups. Heck with he brass! I'd shoot that baby with all the Lapua I could muster. Can't really ask for more than that. SImply awesome!!!!!!!!!!!!!!!!!!!!

Alex