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Thread: Barrel length vs Velocity planing an experiment

  1. #1
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    Default Barrel length vs Velocity planing an experiment

    So a little background first. I have a commercial Mauser 98 in 30-06, with a very pitted bore. It shots okay, 1 1/4 groups at best but always under 2" with its favorite loads. The big pain is the barrel fowls real quick and it is a real pain to clean. I have tried polishing the barrel with Tubs bullets and it helped but it is still bad and given the depth of the pits I really can't see them being polished out. Since I have always wanted a 35 Whelen and since I recently picked up a 03-A3 in 30-06 I plan to rebarrel the Mauser.

    This got me to thinking of what to do with the old barrel. Being so pitted, I really can't see using it as a barrel on anything. So I have decided to preform a barrel length vs velocity experiment with it. The current barrel is 23 5/8" long (was 24 but I cut and Redneck recrowned, which helped accuracy). I plan to cut it to 22, 20, 18 and a little over 16" (too stay legal) and check velocity at each length.

    The current loads planed are 56 grains of H4350 under a 180 grain Horniday interlock, this load shots well so I have a number of them loaded up. I also plan to load a faster powder with the same bullet, I am thinking Varget or IMR 4064. I plan to load which ever I choose up till I see pressure signs and then use that load regardless of accuracy. I am currently thinking of 4 shots at each barrel length to get a good average of velocity. The only other bullets I have on hand are some 168 grain, given the small difference in weight it does not seem to make sense to check a load with both of these.

    Okay, finally to the reason for this post. Since after the barrel is cut there is no going back, I am wondering does anyone see a problem with this plan or other things it might pay to try, ie other bullets or powders. I do not want to turn this into a major research project but I also would not want to not look at anything else easy to check while I am at it. Any suggestions are welcome.

    Hopefully it is needless to say; I will post the results here.

  2. #2

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    The experiment sounds interesting. However, not to talk you out of doing it, but why don't you just have that barrel rebored for your 35 Whelen? You can get it done for $225. Much cheaper than buying and fitting a new barrel.

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    I cut my 338 Win Mag barrel down to 22" from 24" and lost only 25 fps...I don't like long barrels and that loss of velocity is pretty meaningless. The difference between 4300+ ft.lbs. and 4200+ ft.lbs. is of very little significance if the bullet is put in the correct spot!!

    Silver Tip
    "If we lose freedom here, there is no other place to escape to. This is the last stand on earth." ...Ronald Reagan.....please never forget this!!!

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    Silver Tip: did the noise go up when you cut your .338? Mine is 26" and it seems way too long, but it is sweet to shoot.

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    It would be interesting to some to use cast bullets as well with enough powder such as red dot or unique to get a starting velocity of about 1800fps. If you want some cast bullets to try I'll send you some.

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    Here is an article from a barrel maker on a test that he did with a .338-.378 Weatherby starting with a 46" barrel. Admittedly the results will be a bit different because of the sheer volume of powder that case holds.

    Gus
    http://www.riflebarrels.com/articles...l_velocity.htm

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    Pretty interesting. It seems, by that a 24 barrel is just as good as a 30. To me it is not worth it to carry a longer barrel for a few FPS. Most of my hunting rifles are 24" and I just picked up a model 70 in a 30-06 and it has a 22 barrel. Boy it did seem pretty handy and quick to shoulder. I have not fired it yet so I will find out what a difference it makes when I get to range and shoot at 1,2, and 300 yards and see what it will do.

    Gus
    http://www.riflebarrels.com/articles...l_velocity.htm[/QUOTE]

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    Much depends on the owners' intended use, and a great deal on aesthetics. Some don't like long barrels. Some do.

    With the early English and Continental rifle stocks a 26" barrel properly balances the rifle. American abomination stocks....well, there just isn't anything that will make them look good. Except maybe a roaring fire and marshmallows and Oscar Meyers.
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    I bought a stainless Winchester Classic .375 H&H. I had the barrel cut way down and the new Hogue stock fit to me to work better with a thick coat. It's awesome. It handles much better with in the shortened version. Shoots a tad bit more accurately. The crown on the barrel was fine before it's haircut so I'm thinking a longer barrel has more of an opportunity for harmonics and barrel flex to cause problems on top of everything else.

    It's extremely quick handling and well balanced now, much better than before:


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    Here I start a Thread and then completely forget about it.

    A number of interesting issues have been brought up.

    I have thought about a Rebore and yes the price on them looks good. Several reasons I do not plan on going that way. This barrel is rather thin so I am not sure if it could be rebored to 35 cal. Also, I have some machining experience so I believe I can headspace the barrel myself and would like to give it a try. So even if it turns into more work and time I would like to do it for the experience. Refinishing the barrel is not a big concern as the old barrel needs refinishing anyway.

    rbuck351, I am not sure 1800 would be doable with red dot or unique, kind of high velocity for that fast of powder. If I understand your idea though would be to try a powder even faster then I was thinking to see what the results would be, not a bad idea. I think I will do that I have some 170 grain cast and some red dot, which I could load up. I think I will do that, thanks for the offer of bullets, I have some here so no need.

    Neat links, some good reading there. I know this has been done before but It can't hurt to do it again.

    On the rebarrel I think I will go somewhere between 20 and 22 inches, that should be enough to get good efficiency out of a 35 Whelen. Currently I am leaning toward 20 inch but I may start at the new barrels 24 inch and then cut to 22" and then maybe 20 if the velocity does not drop much between 24 and 22.

    It look like this project is growing out of control like most of my projects do. In any case I will not have time to do much with it till after new years.

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    The larger calibers seem to lose less per inch than the large case small bore rounds. I have a 350 Rem in 24" that gets 2800 with a 225gr. I believe you can get 2600+ with the old 18"carbines in the 350. The 35Whelen is so close as to think the results would be similar. Unless you are wanting a real short rifle, 20/21" in a Whelen would make a very nice handling rifle and the velocity loss wouldn't amount to much.

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    there will undoubtedly be plenty of barrel to bore to .35 - I just had JES do my Montana 270 WSM out to .338 and Jesse didn't even measure the OD on the barrel, just shrugged and said "sure there is" ... it turned out great -

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