Accuracy of new versus once fired brass

[Viperdoc]

I have been working up loads for my 7.7 Krieger barrel in 223. So far, off a rest, it seems to like the 69 and 75 SMK compared to lighter bullets, but still, I am hard pressed to get five shot groups consistently tighter than around an inch, no matter what I try. At this point I do not know whether it is my bench technique, or something about my reloads, or perhaps it's the barrel itself.

Anyway, in working up new loads, I have been using new Lapua brass that has been full length resized with a Redding type S die, and then chamfering the necks and trimming to length in a Gracey. I have a bunch now of once fired brass that has undergone essentially the same treatment.

Should I expect more or less accuracy from the once fired versus the new brass? They have both been resized using the same die, and trimmed to length, so shouldn't consistency be around the same?

 

[fdshuster]

All of my new Lapua brass, ( 222,223, 220 Russian, 6BR & 308) will have loaded round runout of up to .004" with the first loading, and I believe that runout will effect group size at least to some degree, so will not use it in a match 'til the 2 nd or 3 rd firing, by that time it's all straightened out nicely. Other than that, I've never been able to establish any effect on group size's between new & old brass. I have some 6BR Lapua brass that has been loaded 37 times, never annealed and it is still problem free.

 

[Varminator]

I have some 6BR Lapua brass that has been loaded 37 times, never annealed and it is still problem free.

I hear the too expensive remark from people that see I always shoot Lapua in every gun I can shoot it in. If you do the math the Lapua brass is not only accurate but the cheapest date in town. When I hear 37 times, I don't even bat an eye. I have 6mmBr brass that I started shooting in an XP-100 in 2004 and then loaded for a 10 tw rifle and then formed into a 6Dasher no turn and then necked turned to use in a tight neck 6Dasher and then formed into 22Dasher that I shoot for just fun on a cut down 14 tw 22-250 barrel and the primers are still tight but I'm starting to have some become hard to extract after they are body sized so I'm retiring the ones that extract hard. Total number of reloads? Unknown but way more than you could expect from anything other than Lapua I'm actually not prepared to say what I think because it eclipses 37 by so much that it seems ridiculous I do however anneal every tenth load or so. I average at least a conservative 25 rounds per week and have about 300 pices in process. I have not had as much success with the .243 but am very close. Lapua keeps the head together and also the fireformed load will almost always shoot better than the non fireformed load. I also have good luck with other companies brass by creating a false shoulder for the specific purpose of fireforming, this extends the brass life but only about to 10 reloads.
Mark

 

[Shynloco]

Saw your post and was wondering if you have checked the uniformity of the neck thickness on all your Lapua brass. A close friend who competes in 6mmbr swears you have to have the neck thickness within .002 of each other and no higher a variance. He neck trimmed all my Lapua brass (6mmbr & .223) and my finished cartridge runout loading with Wilson Dies measures .002 using a Hornady Concentrity Gauge. My five shot groups (shot out of a completely stock Savage Model 12 VLP) consistently measure under 1/2" @ 100 yds. I really doubt your problem lies in that Kreiger barrel because that barrel is better than mine. I have reloaded the same 40 Lapua casings 17 times, only neck sized, no annealing and rarely need to slightly retrim (length of casings) any of the casings. Interestingly enough, before I changed over to Wilson dies, using Redding dies the runout was .004 using the Hornady Concentricity Gauge when using the same .223 Lapua brass. Hope you find your cure because that 1 inch group stuff would drive me up a wall.

 

[bigedp51]

I was having problems with a Lee Collet die and was on the net looking for answers and ran into an article about Lupua brass and uneven case wall thickness causing "banana" shaped and warped cases in some batches of Lupua cases.

This can happen with any manufactures cases and one poster stated he was buying Winchester cases in bigger lots and having better luck at less cost. Bottom line are your groups bigger on the second and subsequent reloadings or simply put could your brass be causing your problem. Are they banana shaped, warped or misaligned with the axis of the bore after the first firing.

Case Body Thickness Variance

Using the Audette tool, I checked the cases for variance in case wall thickness 0.250" up from the inside of the base. Frankly, I was very disappointed with this result. The cases average 0.003" variance which is right on my reject point for this measurement which I consider this to be the most important measure of case uniformity. Only four of the twenty cases measured were under 0.003" variance and more than that were over 0.003". My Winchester .308 brass rarely hits 0.003" with most falling between 0.001" and 0.002"; even the Winchester and Lapua .30-06 brass is usually in the 0.002" range. Why this brass is distinctly worse, I don't know as shorter brass is theoretically easier to draw uniformly.

http://riflemansjournal.blogspot.com/2010/01/cartridges-lapua-small-primer-308.html

 

[Viperdoc]

The necks, as I recall measuring, were around 0.013. I tried turning some down to around 0.00125, but it made no difference in accuracy. I am shooting off a Sinclair rest on a real rear bag, with a 32x scope. Nomatter the load, the AR still only will get me around an inch or so.

 

[Shynloco]

Viperdoc,
Sorry my friend. Disregard what I wrote because I misunderstood that you are loading for an AR. Bolt guns are a different animal which I was referring too. Obviously I jumped to the wrong conclusion thinking you were talking about a bolt gun. Frankly my experiences are limited loading for an an AR and 1"+ groups are pretty common from what I've seen. The only exception I've seen is a couple of guys who bought "Match" barrels who had their competition dies cuts to match their barrels. And that cost a few more bucks than most guys want to pay unless you are talking competition shooting. Then expect to pay some BIG bucks to make those groups get really tight. But boy are they impressive especially when you are talking Service Rifle Matches where they shoot 600 yds with fixed sights, no scopes. Hang in there and good luck!

 

[KMart]

A possible problem with loading the AR is not having enough neck tension. When slamming the round into an AR chamber, the bullet will move forward in the case neck from the kinetic energy when the round stops going forward. When this happens, you have a variation in OAL of the round in the chamber. I went through some of the same trouble. I went to about .004 neck tension as suggested by John Feamster in his book "Black Magic the Ultra Accurate AR-15"
The .004 neck tension helped me. The other way is to crimp, but I have not figured a way to do that process consistantly.
The tighter neck tension will also help if you are compressing about 25.5 gr of Varget with the heavier bullets to maintain the 2.260 max length for the magazine. The bullet stays in place better.

 

[jonbearman]

I concur with kmart about crimping or taper crimping especially out of an ar-15. Why dont you list the powders and charges you are using.I have found that ball powders work really well in ar's.I use blc-2 and h335 or aa2230 most of the time. Please report back with as much imfo as you have on your loading technique's.What is the neck measure in your krieger barrel,such as .272 or .274.You get the idea.I think we could help you more.

 

[nhm16]

I have an AR with a 18" White Oak Armament SPR contour barrel (1:7 twist). Currently shooting new Winchester brass, use Wolf SRM primers, and load to mag length. I had until recently used bulk range pickup once fired LC brass for costs reasons, but it seems only slightly less accurate than the new Winchester brass.

I found that with either brass, the heavy bullets (69/75/77gr) shoot best out of that barrel with a fairly stout load of Varget or TAC. I can get ~0.6-0.7 moa groups with the new brass. The barrel does not like lighter loads, I have trouble getting less than 1 moa groups with them. I futzed around for a long time trying loads in the 23-24gr range, and didn't get good results accuracy-wise until I upped it to 24.5-25gr (YMMV, IANAL, work up, etc.).

Haven't chrono'ed these stouter loads yet but the lighter, less accurate loads were around 2600fps with a 75/77gr bullet, so they should be faster than that but not quite 5.56/MK262 velocities (nominally 2783fps, beyond my comfort level with handloads).

With 69gr bullets, I seem to get the same accuracy with either TAC or Varget, but with the 75/77gr bullets Varget has the definite edge, TAC is much more finicky. Haven't tried RL-15 though I love RL-7, 10x, and 17 in other calibers.

I use a Lee collet neck sizing die and it gives ~0.002" to ~0.0025" neck tension (along with a Redding body die). Sometimes I use a Lee factory crimp die which doesn't seem to affect accuracy any, but I stopped using it because I'm not having any bullet set back issues and the gun is just a range toy and not used for competition.

 

[BoydAllen]

Viperdoc,
How do you have your rifle supported when shooting test groups? I see a lot of AR shooters that I believe are not getting the best that their rifles have to offer because of how they are being supported and shot from the bench. Generally, they fail to understand how important these factors are, when shooting from a bench.

 

[Viperdoc]

Thanks for all the great feedback! The rifle I have is made from a Krieger varmatch 7.7 with a Geisselle match trigger and Nightforce 8-32 NSX. Free float tube with flat Sinclair adapter off a Sinclair bench rest and br rear rest bag. Still could be my breathing and shooting technique.

Have been using now 1x Lapua brass, CCI 400, neck turning, Redding type S with 0.246 (finished round diameter .249). All primer pockets uniformed between each firing, and each case trimmed and chamfered.

Just got some 52-65 gr varmint bullets, and some 4895 to try along with TAC, H335.

Have a lot of Vargetand AA2520, but everything I've read suggests these powders are too slow (even out of the long Krieger) for the lighter bullets(?).

Other ideas welcome.

 

[DCRYDER]

Have you tried single feeding? This could eliminate the crimping question. i get best accuracy with my AR's using Benchmark powder.

 

[Viperdoc]

I have a sled to single load, but with 0.003 neck tension the loaded rounds should (?) be stable.

 

[bozo699]

Viperdoc,
Has all your grouping been done with first time fired new brass fully prepped and n/k turned but not fired again since initial prep work? If that is the case then yes I believe your groups could get much better with second or third firings as n/k turning doesn't really do you much good until formed to your chamber. As stated by others n/k tension could be a critical factor for your type of shooting. I am not a AR expert by any means but after you shoot your first round and your gun cycles, extract that unfired round and see if it is getting marked up while its being chambered? use a concentricity tool before and after chambering to see if there is a problem in this area.
Wayne.

 

[Viperdoc]

Thanks much for the info. Will try extracting a loaded round and checking concentricity. Concentricity of neck turned brass is just at the limit of measurement of my Sinclair tool- 0.0005. Using a 246 sizer, my finished loads are a hair over 249, so neck tension is about 0.003. Bullet runout just past the ogive and in from of the neck generally is around 0.0002 or less.

I have Varget, AA2520, H335, H322, H4895, and TAC to try. While the gun shoots the 77's well with its 7.7 twist, I would like to work up a load that shoots smaller varmint bullets (discussed on another thread) well- something in the 50-64 range, with 0.5 minute accuracy or better, to use for PDS. I was under the impression that Varget and 2520 were too slow a powder for the light bullets, although this might not be the case in a longer barrel like the Krieger (?)

May need to try, but is my assumption that slow powders like Varget and AA2520 do better with heavier bullets, while H335, TAC, H4895 do better with the lighter bullets, in general?

Thanks and best wishes to all of those who offered advice.

 

[hogan]

Think you ought to be looking at the OAL of your chamber.
Got an RCBS Precision Mic or a Wilson Case Gauge and caliper?
Measure a loaded round or two, fire them and then measure again.
How much did the brass grow?
I intentionally size about .005 under my RCBS tool's -0- reference line.
Those tools are not calibrated for uniformity, each being different; maybe mine has a -0- ref right at Go Gauge dimension? Doesn't matter just gives you a reference and indicator to learn what you have.

I use a Redding S FL bushing die and a .243 bushing. Need taught neck tension in a semi-auto. Not like the bullets are crimped, they still pull easily enough.

Am not the biggest fan of Lapua brass, own a bunch; but none in .223. Winchester, Lake City, or WCC (win) are my preference. Get great results using Hornady 75gr BTHP and 24gr Re15 w/rem 7-1/2.

If you are firing for groups using magazine loaded rounds, are you sure the bullets aren't slipping forward due to minimal neck tension? If single-loading, are you allowing bolt carrier to fully seat the round, not easing it home into breach? Need that uniformity of the full bolt carrier seat...

So many other factors like trigger and forend contour on bags. Got a railed or other forend design that grabs the bags? Badger Ord Sabilizer forend is about the best design for float tube on a precision/varmint AR unless running a plain float tube. Did WhiteOak Precision build your upper? What does Holliger or Krieger say??

Try a bag of Win commercial brass and maybe a .244 bushing. Use a widely acclaimed match load and all components to see if this eliminates any variables. Might try a box or two of Win/USA 55gr ammo as you are interested in light bullet performance. Load your fired brass with the service rifle match load you choose and see how it works out.

Might even want to tune your ejector spring to reduce its effect on your load in battery geometry and reduce battering on ejection. On a match or varmint AR all you need is a nice flipping the case out the ejection slot, not a violent nailing it into the next county. Maybe there is crap in your ejector spring slot and it can't fully compress? All sorts of variables...

 

[bozo699]

Hogan,
Nice post, there is quite a bit of good advice there. I must ask though what or why don't you like Lapua brass? or is it that you just don't like it in a AR platform?
Wayne.

 

[artbosco]

Should I expect more or less accuracy from the once fired versus the new brass?

Given everything has been done just right, a great barrel and a tight chamber where I have to turn brass, I don't look for accuracy to come to the forefront until after I've fired new brass at least THREE times.

 

[bozo699]

Now I know why you here people using fire forming barrels. 150 rounds out of 50 brass just to get it ready for a match is a lot of wasted barrel life ??? not arguing or denying I know its just the way it is.
Wayne.