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338 Lapua Mag barrel

 
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  #8  
Old 12-02-2008, 04:05 PM
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Re: 338 Lapua Mag barrel

Define small loss in velocity.
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  #9  
Old 12-02-2008, 04:50 PM
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Re: 338 Lapua Mag barrel

I'm not sure...how much would be lost?
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  #10  
Old 12-02-2008, 05:07 PM
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Re: 338 Lapua Mag barrel

;) According to my calculations Shortening the barrel by 4 inches should reduce velocity by 100-150 fps. Assuming the 2800 fps and a BC of .768(Sierra)...that only reduces my POI 23.5 inches or 2.3 MOA at 1000 yds(Hornady). Am I missing something?

Last edited by vballcop1; 12-02-2008 at 06:27 PM.
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  #11  
Old 12-02-2008, 06:26 PM
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Re: 338 Lapua Mag barrel

!00 fps will lower bullet impact a lot more thn 4.1" at 1K.
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  #12  
Old 12-02-2008, 06:54 PM
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Re: 338 Lapua Mag barrel

You are probably looking at more of a 200-300 fps velocity loss. Remember that slow burning powder thing I mentioned earlier. With that short of a barrel I doubt you will reach optimum chamber pressure before the bullet exits the barrel. Now if you are lucky and do a lot of load development you could probably manage only about 100 fps loss if you used faster burning powder.

It is like this. In calibers with smaller case capacities a short barrel is a good thing for several reasons. But with large rounds such as these there is a lot of SLOW burning powder behind that bullet that needs to burned up prior to the bullet leaving the barrel. You simply can't burn up that much powder in a 20 inch barrel and you will end up with a combination flame thrower/rifle.

Am I saying that it is impossible to have a good accurate 338 with a short barrel, no, just saying that these rifles really NEED a 26+ inch barrel to get the most out of them. So if you have your heart set on that 338LM with a 20 inch barrel go ahead and do it. But the answers you'll get here will all say the same thing. For this round long barrels are good.
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  #13  
Old 12-02-2008, 07:04 PM
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Re: 338 Lapua Mag barrel

Sorry, :( I have edited the original post. The correct drop is now listed. That's what I get for working while I'm typing. HA! But I have more now that I've had a minute to do the math. Apparently everyone has an opinion, but I'm the only one willing to put out the facts.
The exact muzzle velocity change I can't determine with my data, but it should be just around 100 fps. Now for the details..

That translates into 23.5 inches difference at 1000 yds. You might say this is significant, but lets compare... The overall drop is now 293.8 inches!! So how much difference is that 23.5 inches? Well the beloved 308 winchester at 1000 yds even at the apparent loved barrel length of 26 inches drops a 200 gr bullet 540 inches....I heard the 338 win mag mentioned...it drops the same 300 gr slug 422 inches at 1000 yds. The lapua is still 128 inches better than a 26 inch barrelled 338 win mag even at 20 inches. Seriously I'm not busting anyone's balls. I can argue ballistics all day, but I want to know if anyone has used a short barrel and how it worked. I'm not a first time gun owner and I think this would make one heck of a rifle.
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  #14  
Old 12-02-2008, 07:16 PM
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Re: 338 Lapua Mag barrel

I actually found a link that gives a similar powder chart and barrel length test. The gun used was not a 338, but it did use the same powder as in the 338. The barrel was cut in 2 inch increments and the results were around 115 fps. I really thought it would be more myself, but that's why I'm looking for someone who has already done it. I'm not sure burning my eybrows off is my desired result. LOL. I really would love to find out what the exact numbers are. I'm trying to wiggle them out of Beretta, but since the gun is not civilian production they are not very open to sharing:(! I do appreciate your insight. Like I said, I know what it sounds like! I just figured there's someone who has already tried it or has a direct answer about the actual minimum barrel length required to reach the max pressure. Feel free to keep posting..I have to go my 1 year old is ripping my printer apart! Thanks
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