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Topic: Reloading 6.5CM for Semi-Auto (Read 150 times) previous topic - next topic

Reloading 6.5CM for Semi-Auto

After many years of reloading and shooting BA rifles exclusively, I acquired a JP LRP-07 in 6.5CM and need some advice in getting started reloading for it. There are some obvious differences in loading for a BA vs SA rifle, including:

-Optimal powder charge is not determined by chrono data and group - reliable cycling has to be considered.

-The rifle has an adjustable gas block so that is another variable.

-COAL/CBTO are determined to a large extent by mag length so chasing the lands for accuracy seems limited.

-Brass prep will be different – I FL size for bolt guns so that won’t change but I assume a little more bump will be necessary for reliability and maybe more than .002” bullet tension

-Optimal bullet weight may be less than the 140 range that usually yield great results in a bolt gun

-The H4350 I use exclusively for my BA loads may not have the best pressure curve for a SA.

I appreciate any input from on these points, as well any specific loads that have been found to work well in SA rifles. 

Thanks,

Dave

Re: Reloading 6.5CM for Semi-Auto

Reply #1
david 41 im not to sharp on the ar stuff but have always heard a guy needs to bump the shoulder back .003 to .004 and run around .003 neck tension... i would think the 140's and h4350 would work fine in one... a barrel is a barrel... play with the gas block to get it to cycle right... i would do my load development at the seating depth you need to fit the mag... and then shorten them if need be..
Grant

Re: Reloading 6.5CM for Semi-Auto

Reply #2
 HI Daved 41, I have an AR variant in 6.5 creedmoor also. I found that with the magazine length restriction 130 grn bullets worked better for me. Other guys use the 140's and do well also. I am using the Berger 130 grn hybrid OTM tactical which is not as fussy about bullet jump as some others. H-4350 behind them. 
 3-4 thousands bump should be fine. I used a chrono to look for a node the same as I do with any other rifle. I decided on a good load at a lower velocity than I would have with a bolt gun, about 2750 FPS. YMMV
 Does your JP have an adjustable gas block? Some AR's tend to be over gassed, and if you adjust the gas so it's just enough to keep the bolt back on the last round, the gun will shoot much smoother and your brass will fare much better.
 My case necks are sized 2 thousands under, but I anneal the cases after every firing so I don't get any spring back and the tension stays consistent and does fine for me. If you ever have a jam or feeding problem, check to see if a bullet was shoved back into the case for obvious reasons. I'm sure the JP, once you get a hand load worked out, will not miss a beat and run like a clock.
  I started with 300 new Alpha Munitions cases, and am on the 4th firing now. They are holding up great, and I have not needed to trim them yet. Primer pockets are still tight as new, but as mentioned before, I am not pushing for velocity in this rifle, I have bolt guns for that.
 Good luck, and keep us posted on your results, there are some guys on here that are experts on these AR type guns, and I'm sure they can tell you much more than I.


Re: Reloading 6.5CM for Semi-Auto

Reply #3
I use the 140gr Bullets and H4350 in mine .003 bump. A lot of guys prefer the 120gr bullets in SA’s I would suggest the JP high pressure bolt if your going to run the heavier bullets mine pierced primers until I stitched to the JP bolt.

Re: Reloading 6.5CM for Semi-Auto

Reply #4
Your chamber will tell you about the shoulder bump.
Mine wants .002" longer shoulders than the other two bolts I have.
Symptom was a few light strikes when shoulders where same as BA.
So I separate brass SA vs BA.
 Also the AR beats up the brass pretty bad, another reason to keep the brass separate.
... rule #9 ...

Re: Reloading 6.5CM for Semi-Auto

Reply #5
Your chamber will tell you about the shoulder bump.
Mine wants .002" longer shoulders than the other two bolts I have.
Symptom was a few light strikes when shoulders where same as BA.
So I separate brass SA vs BA.
 Also the AR beats up the brass pretty bad, another reason to keep the brass separate.
 
 +1 on the brass abuse done by an AR.  Definitely keep the brass separated if you are shooting a BA in the same caliber.
Bob
If everything seems under control......you're just not going fast enough

Re: Reloading 6.5CM for Semi-Auto

Reply #6
I shoot Hornady 129 SST thru my AR-10 with great success. harvested a really nice Aoudad ram last year with one shot thru the chest. I only had Hybrd100V powder available and it give me really good velocity and accuracy. I lost my notes on that load or id be happy to share it with you.

Re: Reloading 6.5CM for Semi-Auto

Reply #7
I own a Rock River Arms in 6.5CM.  Not knowing what it would 'like' I bought boxes of all the brands and bullet weight factory ammunition.  It 'liked' all the bullets in the 140s weight class better than the lighter weights.   Was happy with performance of the factory loads, so only try to mirror those in my reloading.  No issues loading to mag length, 2.80, 2.81.  Bumping .002.   It functions as it should and cycles all the loads and bullet weights.  It is hard on brass and like another commenter I separate it from the brass I use for my BAs.   So agree with all the comments above.  Real enjoyable rifle to shoot.