AR OCW



  • Ok folks,

    I've got my 500 pieces of LC 16 brass sorted out. They've been decapped and half are tumbling as I type. Next they get annealed, bumped 4 thou, trimmed and loaded for a pressure and OCW test.

    Stupid question: Is an OCW the same with an AR15 as with a bolt gun, or should I expect something different? More moving parts, gas tubes, feeding semi automatically from a magazine, crimps... my experience in this regard is limited to progressively loading thousands of rounds based off a book recipe for CQM and blasting.

    My plan is to load a 69gr smk at mag length with Varget and see what happens as I increase the charge 1/10th at a time.

    Anything I missed, tips or things I should look out for?

    Thanks all



  • When I did mine I followed Orkans article and came up with a nice load with no issues. Same process as a bolt gun. I just didn’t mess with seating depth because mag feeding was a must for me.



  • @norcal_in_az

    Thanks for the reply. Thats kinda what I'm planning on doing, I've used that piece before and to great effect.

    I was just curious due to the dynamic nature of the AR15.

    Out of curiosity, what are you getting in terms of SD and ES? I've never bothered with checking an AR and I'm wondering what I should be expecting.

    Thanks again.



  • I wouldn’t load them .1 grain increments though I go .3. If you run them too close together it gets hard to see the node. As for SD I still find it pretty easy to keep things down in the single digits on gas guns just like bolt guns. Good luck with Varget I’ve never found a .223 that would shoot varget very good.



  • First run through OCW on .223 sized case is good for .3gr increments. The second run through of verification you can go to .1 to further refine things before moving on to seating depth.



  • Thanks for the replies everyone.

    @bull81 what powder do you recommend? I’m shooting for temperature insensitivity here.

    I’ve gotten pretty decent results with CFE and BLC2 previously but temperature swings....



  • Varget is always worth testing. Also H4895.



  • @tackyp said:

    Thanks for the replies everyone.

    @bull81 what powder do you recommend? I’m shooting for temperature insensitivity here.

    I’ve gotten pretty decent results with CFE and BLC2 previously but temperature swings....

    By all means test varget I always do but just never have any luck with it in .223’s. I usually have best results with either IMR 8208 and H4895 both of which are temp stable. Also if you don’t have any luck with the 69 gr smk’s the 73 gr eld have done very very well for me at mag lenght in Rainer barrels which I believe is what you said you were running.



  • Thanks for the replies.

    I’ll slap together a couple OCW tests with both powders and see what happens.


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