Accuracy Issues

[Jollymon32]

First and foremost, I am not a noob in terms of reloading or accurate shooting.  

 

There is something wrong with the latest batch of rounds I have loaded.  To validate my suspicion, at today's steel challenge match, I shot 10 of these rounds against a steel plate 10 yards away - 6 hit, 4 were flyers.  I used a buddy's hand loaded ammo, same test - all 10 were on target.  I am usually a very good shot with my Accushadow. (Obviously, today's steel challenge results sucked ass...)

 

I knew something was 'OFF' when at the last USPSA match, I was having a hard time hitting steel, and an easy time hitting no shoots that were offset of the target.  Of the hits that were on paper, all were perfect diameter hits, I.e. bullets were not tumbling.

 

So what changed....

 

This is my first batch of FMJ rounds.  Prior to this batch and with great accuracy results I have loaded over 70K rounds of RN plated and RN coated bullets - the last 20K were RN coated .356.

 

These rounds are RMR .355 RN FMJ 124 gr.

 

When loaded, the round, at the base of the bullet measures .3790.  I do not believe this is a crimp issue as this measurement is within 9mm specifications.

 

I have 'pulled' 5 bullets, randomly, and the jackets are not marred or damaged - again pointing that this may not be crimp issue.

 

The powder is Sport Pistol, 4.2GR for an average power factor of 127.5.  All rounds are case gauged to eliminate any split cases or cases that do not meet specs.

 

The LOA of the rounds are 1.13.  For this specific bullet, the CZ barrel allows for 1.136 in the plunk test.

 

The pistol is an CZ Accushadow (Gen 1).

 

The reloading press is a Dillon 650, with a Redding Competition seating Die, followed by a Lee Factory Crimp Die (FCD).  On the FCD, NOTHING has been changed between the coated bullets and the FMJ's.

 

I am getting flyers where usually I do not get any.

 

Any insight is appreciated.

 

THANKS!!!!

Edited August 18, 2019 by Jollymon32

[Sarge]

Changing ANYTHING in a recipe requires me to go to the range with several different loads to shoot them. I shoot for groups from a rest, I run over chrono etc. When you say flyers, there is no way to know if its just a really bad group or if there are actually flyers. I hope that makes sense. I shot my first reloads for a year and things were great. Then I got some different bullets of the same weight and profile and all of a sudden had a lot more C's than usual. After a few months I finally went and shot groups and was lucky to put ten rounds on a paper plate at 25 yards or so. I was shocked to say the least. I went back to the drawing board and made several different loads, with different charges, lengths, etc until finally one load was back to grouping at 2-3 inches which is about as good as I can hold.

  If it were me I would load batches of different specs and go shoot them from a rest to see if that helps find the sweet spot. If you still have actual flyers I would check some bullet measurements and see if some are too small or otherwise out of spec. 

This may take awhile so maybe order some more of what you know has worked well before. This will give you time to do some testing.

[superdude]

First, we need details.  Which RMR FMJ bullet?  115 grain?  124 grain?  147 grain?

 

Also, when testing, shoot off a bench at ~25 yards and at a paper target. 

 

Shooting off a bench will help to reduce error that YOU might contribute to accuracy.

 

25 yards is a good distance for most handgun accuracy tests.

 

Shooting paper might help identify if the bullets are doing something crazy like tumbling.

[Hi-Power Jack]

40 minutes ago, superdude said:

 

shoot off a bench at ~25 yards and at a paper target. 

 

Unless you know where the bullets went, you don't know enough

to diagnose or solve the "problem".

 

See how large your group is, and where it is -  from what you've

told us, it is possible that you are shooting 1" groups at 25 yards

with this new ammo, but it's hitting 6" high.  That's a different

kind of problem than shooting 8" groups in the center. 

[Jollymon32]

Added some additional details ( bullet weight and no signs of tumbling)....

 

I have not performed a bench rest test yet.  Although I do extensive ladder testing when I change anything, of my standard recipe, I had not seen the need for accuracy testing until now.  

 

Everything I had loaded up to this point was spot on.  Maybe my gun does not like FMJ.....

 

[Dwbsig]

I would try loading a few to try at .010 and .020 shorter then what you are loading and try them. I have a s2 and I got my beast accuracy at about -.020 from the lands.

[4n2t0]

Did you try the rounds in any other pistol? Could the Lee FCD (I hate that thing) be swaging the FMJ's? Did you chrono the rounds or is 127 PF just a carry over from the original recipe? FMJ's need a little more powder to get going.

Edited August 19, 2019 by 4n2t0

[Jollymon32]

31 minutes ago, 4n2t0 said:

Did you try the rounds in any other pistol? Could the Lee FCD (I hate that thing) be swaging the FMJ's? Did you chrono the rounds or is 127 PF just a carry over from the original recipe? FMJ's need a little more powder to get going.

Is there anyway see if the rounds are being swagged?  I pulled some bullets and did not notice anything on the jacket.  I don’t believe I have an unloaded bullet to compare the pulled ones against...

[4n2t0]

Without an unloaded bullet it'll be hard to know for sure but other than the charge being too light for FMJ's that's the only thing I can think of that would affect accuracy. Your barrel might not like the size of the bullet. Also, just for shits and giggles I'd load a few rounds at 130ish PF and see if that performs any better.

Edited August 19, 2019 by 4n2t0

[Aircooled6racer]

Hello: Are the bullets you are using seconds or pulled bullets? How clean is your barrel? You may have a build up of lead or coating that is causing problems. The exposed back of your bullets maybe causing some problems so I would try some JHP's as well. Thanks, Eric

[GMP]

If you shoot .356 coated without issues its not the bullets.  I loaded 1000's of RMR 124 FMJ with your same load and they have been excellent in four different guns to 25 yards,  but no Lee FCD(hate that thing too). Just a thought but could your barrel have some remaining lead fouling from coated?  I have had terrible luck with leading using 356 coated in CZs and load .358s.  

[Yondering]

11 hours ago, Jollymon32 said:

Is there anyway see if the rounds are being swagged?  I pulled some bullets and did not notice anything on the jacket.  I don’t believe I have an unloaded bullet to compare the pulled ones against...

 

Pull a few bullets from your loaded ammo and measure the diameter. If they're smaller than the .355 they started as, they're being swaged down during the loading process. Measure some before loading to compare. It's best to do this with a micrometer rather than a dial/digital caliper, for accuracy.

 

It's unclear from your posts - did you just swap bullets in your load and hope for accuracy, or did you work up a new load with the new bullet? Load workup should include testing for accuracy at different seating depths and powder charges. At bare minimum, comparing POI of the new load to the old one is important; they won't necessarily hit in the same place.