Odd New .308 Barrel for Project

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10 years 11 months ago #33700 by Lizardette
Odd New .308 Barrel for Project was created by Lizardette
Ok, so it's not AR10 related, but I just got ahold of an FAL barrel (in .308 of course) that I've been trying to pry from DSA's grasp for near two months. It's their "Medium" weight barrel. That is, it's heavier than the standard light weight GI profile, but not as heavy as those on the various Heavy Barrel squad-automatic versions.

All of their barrels are custom made, and it shows. It looks fantastic.

Anyway, now for the odd thing:

I have a muzzle brake I plan to put on it, and decided to pre-check the fit and alignment. First off, it threaded on easily by hand without any lubricant and came back off just as easy. That's weird by itself, but not what I'm posting about. I have an M14 flash-hider alignment gauge that I was planning to check the alignment with. It's precision ground to 0.3000". It wouldn't enter the bore. I removed the brake and tried again. It still wouldn't go. I tried a bullet - point first - but that didn't go in very far either. So, I got out the dial calipers and checked the bore diameter. According to Hornady digital calipers it's ~0.299" across the lands. That is, varying from 0.2985" to 0.299". Ok, fine. Tight bores happen a lot more often than you'd think. Then I measured the groove diameter at 0.304". Just for fun, I took a look at the chamber. The free-bore in this thing might be more comparable to a wartime German Mauser 98k. There's no way to seat a bullet out far enough to touch the lands on any that I've tried. I mean, the bullet wouldn't even be held by the neck if you tried. I've yet to put a bullet in a resized case and push it in to measure the max. OAL (with the bullets we use most often, of course 168 grain SMKs), but I'm willing to bet that it's significantly longer than magazine length. At least it should keep pressures down to a reasonable level, right?

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10 years 11 months ago #33705 by jtallen83
Replied by jtallen83 on topic Odd New .308 Barrel for Project
This is not a topic I'm real familiar with but I would have assumed .308 would have come in to play here? :unsure:
I couldn't find the article but somewhere I read that freebore can help in consistency, any thoughts here?

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10 years 11 months ago #33706 by ernierod
Replied by ernierod on topic Odd New .308 Barrel for Project
I always thought freebore was incorporated in a barrel to reduce the pressure spike,some what,from when the bullet left the case to the time it engaged the rifling.Weatherby used this method to allow a saftey margin in his high pressure cartridges and achieve a higher velocity-I believe
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10 years 11 months ago #33786 by SOC
Replied by SOC on topic Odd New .308 Barrel for Project
Contact DSA and ask them. It may be a defect. I've built FALs and even on Mil barrels the freebore was not that excessive.

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