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.



  • @tackyp
    Any update on the results?



  • @bull81

    Not yet. This Friday.

    I’ve got two sets ready to go; 69 SMKs and 77TMKs.

    I’ll keep you posted.



  • @tackyp said:

    @bull81

    Not yet. This Friday.

    I’ve got two sets ready to go; 69 SMKs and 77TMKs.

    I’ll keep you posted.

    10/4 just curious bud.



  • I’ve been meaning to update this as I went.

    Ran through my final OCW test today and found a load I liked for the AR I’ll be using for the competition.

    77smk over 23.5gr H4895, LC case, CCI 450. 2.255OAL.
    It shot a touch over a half inch in the rain and wind off a bench for a 5 shot OCW group.
    Next step is to work out the velocities and confirm dope.

    In playing with this rifle I also tried varget and found a very good load at 23.4 gr. This gave me a really good SD and ES of 6 and 14 respectively, but unfortunately the velocity wasn’t good enough (2560) to get me to the long targets and stay supersonic. Also it was dirty as hell, and these guns shit where they eat.

    I’m not planning on playing with the seating depth because mag length is a requirement, SMKs handle jump well, and I can’t imagine seeing any improvement getting further back from the lands.

    I might throw a crimp on a few and see if that does anything for me.



  • @tackyp

    If you have time adjusting the seating depth can be beneficial in reducing ES and SD’s too. Just something to consider as a fine tune.



  • What type of competition?
    3 Gun or something like F Tactical?



  • @hypo

    The idea is a practical/tactical carbine course. Think PRS style competition with both shooter and spotter on a team. One bolt gun, one carbine.

    Lots of moving and shooting and shooting from strange and awkward positions, under stress.

    It sounds like it’s going to have targets from CQM distances all the way up to 500 yards, but with the option to take shots out to 1k for bonus points, thus my need for speed to get there.



  • That sounds like you need to be in decent physical shape too.

    I could probably shoot small bore bench rest dragging an oxygen bottle along with me.

    Heck, maybe even a Steel Challenge Pistol Match if the plastic tube doesn't get in the way of the draw...

    I am going to turn 50 this Fall.
    At least 20 more years to go I pray.
    Dad is 72 but fighting CHF.
    No bottle for him yet.

    Get out there and live life to the best of your ability.
    We only get one shot at it.



  • @hypo

    Yeah the first day of the competition features a 20 mile land nav/ruck march through the wilderness outside bend Oregon. Something like 5000 feet. The idea is we get points for things like problem solving and obstacle courses, along the way. I’m counting on making up points that I’m gonna otherwise lose shooting.

    I’m one of those special idiots that runs marathons for fun.



  • Nope, you aren't an idiot, I am.
    Cardio conditioning is Money in the bank.

    I am a 30+ BMI truck driver that has to pass a yearly physical to keep my job.

    220 is my goal weight by Christmas.
    Hungry right now.
    Keeps me awake though.



  • Settled on 23.5 gr of H4895 under the 77SMK and a CCI 450.

    It’s giving me 2740 from a 18inch 1:8 Wylde chamber.

    My ES and SD is a little higher than I’d prefer, but it’s nothing outrageous but I have the velocity to get to the long targets.



  • @tackyp
    Good luck at your competition fella


 

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