OAL Problem

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12 years 2 months ago #16823 by bipe215
OAL Problem was created by bipe215
I have been loading 168 gr SMK at 2.80 oal in my new AR10T. I just got a Hornady oal gauge and found out that at 2.80 I'm still .074 off the lands. I have determined that I can go out to 2.855 and still fit in the Armalite mag. Of course I'm still about .020 off the lands at that length. Does anyone else have experience reloading for a 'long throat' AR10?
I should add that my friend 'Keifer T' on this forum, has the same gun just a few serial numbers from mine (we bought them the same day) and he is just
.020 off the lands at 2.80 oal with the same load.

Steve

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12 years 2 months ago #16839 by foxhunter
Replied by foxhunter on topic OAL Problem
I am no expert, so probably no help on this. I only try to get on the lands with my bolt guns, but I don't target shoot except on my own range. Given that the bullet will likely move forward out of the case up to .007inches or more when the bolt slams the bullet forward in an AR, I am more concerned with keeping the bullet in the case than having it fit in the lands, so I keep my bullet length at 2.81 for all my AR's.

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12 years 2 months ago #16840 by bipe215
Replied by bipe215 on topic OAL Problem
I think if I do seat some on out closer to the lands I'll probably use a light crimp. Hornady also has a spire point with an odd ogive that is closer to the tip that might help alot. The problem will be finding them.

Steve

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12 years 2 months ago #16845 by LebbenB
Replied by LebbenB on topic OAL Problem
By going with a lighter crimp on a semi-auto, you run the risk of bullet setback as the cartridge gets jostled in the magazine and as it feeds into the chamber.

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12 years 2 months ago #16848 by 13fcolt
Replied by 13fcolt on topic OAL Problem

LebbenB wrote: By going with a lighter crimp on a semi-auto, you run the risk of bullet setback as the cartridge gets jostled in the magazine and as it feeds into the chamber.

Truth.
There is also the likelihood of knocking the bullets out of coaxial alignment, sending them down the barrel slightly skewed off center, hosing your groups.
Neck tension is one of those things that must be experimented with to get just right for accuracy. For practice fodder, a good solid factory crimp will suffice.

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12 years 2 months ago - 12 years 2 months ago #16876 by BUILDING MY SASS
Replied by BUILDING MY SASS on topic OAL Problem
I guess I am not that worried about all that with my loads...
I full length re-size, trim, measure...around 2" and set my bullets accordingly..usually just under 2.8..by a .001 or so..then Crimp..light.
Haven't had any issues..but with the winchester brass...I only load them 3 times and discard them...
I think someone needs to contact Zfk and get him in here...He is the Reloading Expert...
BMS
Last edit: 12 years 2 months ago by BUILDING MY SASS.

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12 years 2 months ago #16878 by bipe215
Replied by bipe215 on topic OAL Problem
Thanks for the replies. I had no idea that there would be that much difference in factory chambers. Though it wouldn't be any fun if everything was identical and one load was perfect for all.

Steve

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12 years 1 month ago #18702 by wvfalcon
Replied by wvfalcon on topic OAL Problem
Glad I got on here and review the above comments. I have for years loaded all kinds of ammo but just now attempting to load for my LAR-8. I had planed to load @ 2.800" with a 168gr SMK but now intrigued on how far the lands are ahead of the throat. Limited to magazine constraints there should not be to much effort to find the COAL. Interesting points on crimping. Thanks all.

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