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charger 1
04-02-2008, 06:53 AM
Is the design of bevel bases intended to help the gases get up the side and cut more off or what? I just dont get the point

cuzinbruce
04-02-2008, 07:14 AM
Bevel base bullets are designed that way for two primary reasons, neither having anything to do with accuracy. One is that the bevel base prevents the rounded edge you might get if the mold or metal wasn't hot enough. So the boolit LOOKS filled out properly even if your technique was off a bit. The second is that the bevel base requires less expanding of the neck before seating and is less likely to shave lead off the boolit when being seated. Especially with progressive loaders or loading machines.
As for accuracy, well, they do come out the muzzle of the gun. Some people report good accuracy. Others (including Handloader magazine) are less than enthusiastic. The complaint is that they don't seal the bore that well, which is exactly your point.

Bass Ackward
04-02-2008, 07:37 AM
Another thing that they do if you have a tight tolerance gun to appreciate it, is that they align better in the case. If your dies crimp concentrically, then they will correct alignment. But if you are taper crimping, then this can be a plus.

But I do well with some BB and some not. Just depends on what's happening. But if you are shooting a light bullet that has a short bearing area and you bell, you get almost no case neck tension. So everything's a trade off.

Bret4207
04-02-2008, 07:51 AM
Dat dere bevil base, she no goot in my book! Ease of loading is the primary purpose. One less thing for the big volume loader to worry about.

bullshot
04-02-2008, 07:57 AM
Maybe wrong but I was under the impression the bevel base was designed for commercial casters because they fell from the mould easier.

oso
04-02-2008, 11:34 AM
I look at a bevel base as a bobbed boat tail.

MtGun44
04-03-2008, 02:23 AM
I think cuzin put his fingers exactly on the two reasons. The easy loading
story is commonly reported, but I think the commercial casters like
the 'looks good without a good base fillout' is a real world reason.

Bill

mtgrs737
04-03-2008, 09:28 AM
The BB doesn't show handling dings like a sharp 90 degree corner would, that's another reason the commercial casters like them.

txpete
04-03-2008, 09:40 AM
one of the first molds I bought for my master caster was a magma 200 gr swc BB.same mold the commerical guys use.it is a very accurate bullet when not at 22 bhn:).
4.5 grs bullseye and that bullet in my 1911 is the most accurate load so far I have shot.I think that wax lube and a bullet being way to hard has been a problem for alot of people with BB bullets.
pete
ymmv

Dale53
04-03-2008, 09:53 AM
txpete;
You may have something there. I have cast and shot thousands (and I mean THOUSANDS) of .45 ACP 200 gr SWC's and some have been plain base and some have been bevel base. I have seen little or no difference in accuracy.

My favorite bullet for .45 is the #68 H&G. However, couldn't afford a H&G four cavity mould at the time so settled on a Saeco #68. It is not the same design, but close. It is bevel base and shoots VERY well, even for critical NRA Bullseye shooters. My guns are smithed to function and shoot well with most any design, so the difference in feeding potential is a non problem for me.

Some time later I had a chance to buy a #130 H&G four cavity mould at an attractive price. I bought it and it casts so well (the bullets just fall out of the mould) that it has become my favorite .45 ACP bullet in spite of the fact that the design is not my favorite. It is plain base and shoots match level (doesn't cut quite so clean a hole but functions well in my 1911's and also works "a treat" in my 625-8). So, for reasons a bit remote from "most desirable" this bullet is now the "go to" bullet for my .45's.

Now, I am ambivalent on the 'bevel base" question (don't really care one way or the other).

Dale53

xtimberman
04-03-2008, 09:58 AM
My main objection to BB designs is that gas-cutting around the bevel can create unnecessary and excessive leading in the barrel throat and beginning of the rifling.

With many light to moderate loads using BB-design bullets cast of certain hard alloys, leading can be severe. I first ran into this when loading light plinking loads in .44 Sp/mag and .45 Colt with Magma-design BB bullets from Lasercast and Meister. Where did all that leading come from when my cyl. throat, bore dia., and bullet size were matched up?

IMO, when everything is matched up dimensionally, and you're getting a lot of leading in the beginning of the barrel, you can usually lay blame on that bevel base.

xtm

txpete
04-03-2008, 10:35 AM
try WW and some lee tumble lube.I have shot "tons" of the magma 250 gr lfn out of my rugers even my win 94's using my alloy without the leading that your talking about.
pete

xtimberman
04-03-2008, 11:05 AM
try WW and some lee tumble lube.I have shot "tons" of the magma 250 gr lfn out of my rugers even my win 94's using my alloy without the leading that your talking about.
pete

Likewise, I have shot many heavy loads using the magma BB designs with no leading. Also, I can shoot Magma BB bullets of WW alloy or softer from my buddy's mould with no problem in heavy or light loads. They will obturate properly and not gas cut with any of the good lubes I use. :-D

If you read my post carefully, I mentioned "certain hard alloys" - Lasercast, Meister, and another local one, KEAD, all seem to fit that category - in my experience.

I really wasn't referring to leading caused by the friction of high velocity and a lube that isn't up to the task. I was talking about gas-cutting leading from lighter loads that won't obturate certain hard alloy bullets properly - and the fact that the bevel base design is probably to blame - since PB bullet designs do not normally have this problem. :neutral:

xtm