27 inch vs 20 inch RPK


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csa77
April 28, 2012, 02:56 PM
I noticed today that 308 veprs are available in not only 20 inch barrels but now also 27 inch.

I like the look of the 27 inch since its more closer to the svd length. but
would a 27 inch barrel cause any flex in the gun while firing to be greatly exaggerated by the time the bullet leaves the barrel? part of me wonders if the 20 inch might be more accurate


anyone have any thoughts on this?

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TurtlePhish
April 28, 2012, 04:58 PM
The 20-inch will probably have less flex, hence being more accurate, but it'll also have quite a bit less velocity than the 27.

Buck Kramer
April 28, 2012, 06:03 PM
Watch a slow-mo vid of an Ak type rifle firing. When the bolt carrier slams rearward to the back of the dustcover the end of the barrel flips upward and then kind of flops back and forth. It does not throw off the accuracy that much in 16-24" but I can't imagine a 27".

Turtlephish-I'm not exactly sure a 27" would have more velocity than a 20" but the 20" would have more over the 16". I tried my google-foo, but I didn't work. I know there is diminishing velocity the longer the barrel PAST a certain point, I just dont know where that point is...

mshootnit
April 28, 2012, 06:10 PM
I don't know about the longer barrel but I can attest that at least one Vepr 20" 308 is capable of 1.75 MOA accuracy

briansmithwins
April 28, 2012, 06:38 PM
20" is already going to be pretty nose heavy and ungainly. I can't imagine what a 27" would be like.

BSW

animator
April 28, 2012, 06:49 PM
Watch a slow-mo vid of an Ak type rifle firing. When the bolt carrier slams rearward to the back of the dustcover the end of the barrel flips upward and then kind of flops back and forth. It does not throw off the accuracy that much in 16-24" but I can't imagine a 27".

Turtlephish-I'm not exactly sure a 27" would have more velocity than a 20" but the 20" would have more over the 16". I tried my google-foo, but I didn't work. I know there is diminishing velocity the longer the barrel PAST a certain point, I just dont know where that point is...
Bullet's already left the barrel by the time the carrier gets to the rear of the receiver.



Me personally, I'd go with a 20", just because of the poor handling offered by a 27" barrel...

briansmithwins
April 28, 2012, 08:12 PM
Actually, the bullets gone before the bolt has unlocked.

BSW

Adam123
April 29, 2012, 08:47 AM
If the bolt slammed back fast enough to beat the bullet out of the barrel, you'd probably have a destroyed AKM in a matter of one magazine.

Z-Michigan
April 29, 2012, 09:22 PM
I have not seen a 27" cataloged anywhere. Only 20" and 23". The 23" is the same length as a real RPK, or at least a common form of the RPK. The 20" is likely made only for the US market. 20" is plenty for any of those cartridges, and 7.62x39mm doesn't gain much velocity from 20" to 23". Some loads of .308 will gain a little velocity, others won't gain any, but none gain very much.

Cal-gun Fan
April 29, 2012, 09:35 PM
The 27 inch is available on atlantic firearms.

Z-Michigan
April 29, 2012, 10:00 PM
Thanks, found it here:

http://www.atlanticfirearms.com/storeproduct1199.aspx

It looks like it was made as a joke, or a flat out mistake. I wonder if maybe it meets some minimum length requirement somewhere to be legal. I kinda doubt that the F-Class set has demanded a VEPR, and I see no other reason for it.

TurtlePhish
April 29, 2012, 10:14 PM
Well... it has a LOOOONG sight radius, for anyone who wants to be super-accurate with AK irons. :rolleyes:

Atlantic Firearms
April 30, 2012, 07:54 AM
http://www.atlanticfirearms.com/data/default/images/catalog/large/Vepr-V308-27-01.jpg

Atlantic Firearms
April 30, 2012, 07:56 AM
http://www.atlanticfirearms.com/data/default/images/catalog/large/Vepr-V308-27-01-2.jpg

Z-Michigan
April 30, 2012, 11:08 AM
Atlantic - what's the story behind these? I never see rifle barrels this long for any purpose besides F-Class and some other types of competition. Even varmint rifles rarely go past 26", and that's with overbore cartridges that get more benefit from long barrels.

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