6.5 CM help/advice

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C-grunt

C-grunt

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Im loading ammo for my 6.5 CM with a 22 inch Gradous barrel.

Loads tested were 41.5 grain and 42 grains of H4350
Each load was a Hornady once fired case (through my rifle), a 140 ELD-M, Federal Champoin large rifle primers, Full length resizing, and loaded to 2.8 COAL. All done with a Lee hand loader

The 41.5 grain load shot better accuracy but it had a SD of 19.

49381075478_f7bc041360_h.jpg 2020-01-13_03-25-21 by chase ditwiler, on Flickr

I yanked one on this group but it still shot a decent group

49381564056_a2fd2fd1b3_h.jpg 2020-01-13_03-31-10 by chase ditwiler, on Flickr


The 42 grain load shot lower SD of 12 but would overall shoot a little less accurately and would throw a flyer every so often.

49381808566_e867b67f1c_h.jpg 2020-01-13_04-35-42 by chase ditwiler, on Flickr

49381346978_a240157ae6_h.jpg 2020-01-13_04-36-00 by chase ditwiler, on Flickr

This 42 grain group shot better but I had a primer that wouldn't ignite so it's only a four shot group (last of my loaded rounds)

49381537671_52db161e4c_h.jpg 2020-01-13_03-24-38 by chase ditwiler, on Flickr





Now I fully acknowledge that the flyers could have been me but those shots felt good and I was shooting off a concrete bench using bags. All the ammo was loaded at the same time and Im not sure why the flyers would be so far off. Im still fairly new at reloading so what should I be looking for to either improve the SD on the lighter load or get rid of the flyers on the hotter load?
 
FWIW I settled on 41.5 gr of H4350 and have used that powder charge with 3 different bullets with best accuracy too. My load manual says 41.7 is max, but I've tried 42. There wasn't much difference in either accuracy or MV between 41.5 or 42 gr. I just decided to play it safe with the lighter load.
 
Do a full benchrest prep of 100 new brass. Then get a custom or fl bushing die. For starters. Have not used a
Lee hand loader
Click to expand...
, may work well??

Is this a proven system? Does your rifle have it?

QUICKLOC BARREL RELEASE
Patent pending system for barrel removal and refit including length change in less than one minute, simply a 4mm hex key. Makes a smaller, less obtrusive package for transportation
Click to expand...
 
243winxb said:
Do a full benchrest prep of 100 new brass. Then get a custom or fl bushing die. For starters. Have not used a , may work well??

Is this a proven system? Does your rifle have it?
Click to expand...

The Lee hand loader works well enough, it's just a bit tedious. Great good someone who doesn't have a lot of room or needs to be able to store it away.

My AI does have the quick change barrel system. I don't take the barrel off for storage/transport. I use it for barrel changes.
 
Some things to double check.

1.Is the rifle riding the bags the same evey time. After firing, is rifle returned to the same position on the bags.

2. Wind flags at 25 & 75 yards.

3. Flyers- sort brass by 3/10 grs, - Benchrest prep, trim to all the same length. Uniform the flash hole. Use brass from all the same lot. Outside neck turn before sorting by weight, if your going to turn.

4. I like my Redding Type S fl sizing bushing die. I found that sizing only 1/2 of the necks help center the round in the chamber, making smaller groups. . The bushing of the correct size doesnt over work the brass. Case life is a lot longer then standard dies. The die allows choice of using or not using tne expander.

5. Testing different primers may make a difference. I have not tested different primers. Using CCI BR2 in my Rem 40X in 243. Neck turned Win brass.

6. When there are 3 or 4 bullets touching on the target, the next shot is a pressure shot for me. I try not to hold the gun tighter or change trigger control. Some times it works, some not.
Make note of what shot is the flyer. Was it a pressure shot?

7. Give each box of bullets a lot number. The next lot may be more accurate or less. Berger Bullets in 243 have been the best i have tried without buying custom bullets.

I am not a benchrest shooter, just trying to shoot ok groups.
 
You may want to test the load at 41.3, 41.4, 41.6, and 41.7 to find the center of the node. You said the velocity was not much different at 42.0. Look at all the numbers and see if the fliers are running at a lower or higher velocity. This is helpful in help determine what is causing the fliers, out of node. Primers can be the problem since your not using match primers. The Fed GM match primers give me the best groups and lowest SD's.
 
May need to work on your seating depth with the 41.5gr load. Seating depth can change the way the sd turns out. Slightly changes the pressure curve
 
first of all, that's great shooting. and a nice rig too. i've been to gradous' place a few times to have him make barrels and he's one of my favorite gunsmiths. and that's a nice scope too.

second, not to dogpile on the lee stuff, but whackamole. if you're doing that good with lee, you're gonna do great with better stuff. i'd recommend you look into LE Wilson hand dies. they're very inexpensive and will probably reduce your runout.

third, given your "flyers", my recommendation is that you perform an experiment. load your ammo and mark each piece of brass. next, go back and without cleaning (other than a quick wipe of any debris from the outside), reload those same cases and shoot them again. and again. the goal is to see if your "flyers" are coming from the same pieces of brass every time, which would indicate perhaps a problem with runout or neck tension or who knows. but basically, you need to start eliminating variables, and i'd start with the brass.

once you've eliminated brass defects, my guess is your groups will tighten up, and then you can tune them with seating depth and powder charge. (i don't think tweaking seating depth and powder charge is going to fix those "flyers". seating depth and powder charge would make a round 3/4" group go to 1/2" or 1/4" but i don't see it taking what appears to be fairly consistent 3-4 shots in 1/3" and flinging one an inch away.

from a casual observation of your groups, my guess is that your right to left is from position and trigger or perhaps a bit of parallax, but is overall excellent. while your "flyers" are mostly vertical, which i'd say is either you giving the trigger a good yeehaw, or something up with the brass, or... an ignition problem, possibly caused by inconsistent seating depth on your primers, given one of them failed to go off. seating primers correctly is super important for low SDs.

edit: also, if you want really low SD, you will have to measure powder very precisely. get neck tension very consistent, and seat your primers fully, and probably use better primers.
 
I agree with @taliv on this, very good shooting indeed...

Unless a maverick shot is completely out I consider them my group no matter how bad it looks I figure out why.
My bipod rifles weather shooting prone or benched absolutely will not shoot as small as a BR , it just won’t happen nor will my BR shoot Smaller than a PPC.
one huge reason is when I magazine feed ammunition im limited on seating depth adjustment . so there’s that!

Things I’ve found that really shrink groups- Wind flags always use wind flags.....www.brflags.com


Powder selection- just caus Bob said so don’t make it SO

brass prep -using quality brass ,neck tension, minimum sizing, case volume

Primer selection -testing side by side

Bullet selection - better bullets shoot better.
Bullet sorting- measure BBTO load only those with .001 swing each session.
Parallax adjustments
Trigger quality or lack there of
Table manners- simply shouldering my weapon in a consistent manner is a huge endeavor for me.
These are some of the area’s I work on for personal improvement.
I’m always trying to improve but I may run out of time before I reach my goal. Lol
Good fortune to you sir
J
 
South Prairie Jim said:
Unless a maverick shot is completely out I consider them my group no matter how bad it looks
Click to expand...

I feel the same.

If I shoot a group with a flyer, even with a called flyer, then repeating the group shouldn’t be an issue. So I’ll either shoot another group, or shoot twice as many rounds into that group. If the flyer repeats, then it wasn’t a flyer - it’s the group the rifle and I are shooting that day. If a flyer didn’t repeat, then it wasn’t a flyer, it was part of THAT group.

Root Cause Analysis process to determine the cause of the flyers, notwithstanding.
 
A flyer is just a shot that was off call. When Cgrunt said the shots felt good but landed a long way away from the rest of them, that’s a flyer. That’s all it is. The important thing now is diagnosing why it happened.

No one is trying to say it’s not part of the group. That’s a total strawman.
 
Btw I’ve never heard of a maverick shot. Is that a midwestern thing?
 
taliv said:
Btw I’ve never heard of a maverick shot. Is that a midwestern thing?
Click to expand...
Yeah a maverick is a hick thing . What’s a straw man??
When my targets are at the scoring table the match director or fella that scores or measures the group never asks me if that shot was a flyer or not.

It’s just part of the group
 
Last edited:
i'm just saying you are arguing that flyers are part of the group. no one is arguing they're not part of the group.
 
i don't mean arguing in a bad way; maybe contending would be a better word? and just because i'm a mod doesn't mean i'm right. we're all just having a discussion. no apologies needed. i think the key is figuring out why one shot isn't with the rest of them, which isn't to say it doesn't count
 
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