View Full Version : Tapered front bands?
01-27-2006, 08:31 PM
Was at Mountain Moulds' website, and fiddling with the specs just for play mostly, and he has that feature in his program where you can specify a tapered front band if you want to. Looks like it automatically takes the front half of the front band, and taperes it from groove to bore-riding diameter.
My question is, would this tapering of the front band be a likely asset in old milsurps that may not have quite symetrical throats? I just wondered if maybe the taper wouldn't at least minimize any non-concentricity by tending to move the bullet more back toward the center of the bore, but I'm not sure of this because of the simple time factor involved, inertia to be overcome, etc. Geez! All this stuff hurts my head when I start trying to figure it all out!
In general, is it better, odds on, to go with a full diameter front band or a tapered one????
01-28-2006, 12:29 AM
.................If the front band is lying in the throat with no contact with the leade then I don't see it's utility. If the front band is in fact bumped up against the leade then it may benefit in helping to center it (at least the FRONT of it 8) ). A tapered front band would have to be tapered at a much more acute angle then the more common gentle 1* to 4* rifle leades. Yet it may be helpfull. If the shooter thought it was improving things, then it probably would. Of course there is the 45-70 Gov't ballseat, ha!
I was going to shoot some Lee 450 and then 500gr slugs in my MAS36 conversion. However, going against all things LEE, these 2 (at least from my moulds) dropped them with noses like .452" or at least .451+". The MAS's magazine will take them at about 3.00 OAL IIRC so in the gov't chamber they were a real pill to chamber.
I put a .451" sizer in the lube press and ran the slugs down nose first. Thus sized they chambered very nicely. The bolt closed smoothly with just a small amount of resistance. I found that with some extra pressure the front drive band would start into the taper of the die's throat and thereby I got a nicely shaped shallow taper on the front band that almost matched the one in the rifle.
The rifle was very accurate with both those (with most anything I fed it actually) two boolits, but I doubt the tapered drive band had anything to do with it. It was just an interesting artifact I could create on the boolit that looked cool.
Now a gently tapered nose to match the leade is another thing altogether.
01-28-2006, 03:32 AM
Putting a taper on a front band or a bullet has been done for a lot of years. Some bullet designs thrive because they start on a taper and go pretty much the whole way. If you have to jump, I prefer a tappered bullet to trying to fit a bore ride nose because it results in a stronger bullet design. All the Loverin designs come to mind here.
01-28-2006, 03:54 AM
311644 has a taper from bore to groove on its front band. Just like any other boolit if it fits the gun, it shoots awesome. If it doesn't fit........
You mentioned mil surplus. My P17 has two very narrow grooves, which says that the bore diameter surface will LOCATE the bullet (coaxiality). On the other hand a bore that has very narrow lands will be located by the surface of the surface of groove diameter. Hence the effect of the taper in positioning the bullet may be different - depending on how hard the bullet resists engraving by the (wide or narrow) lands. The other two forces locating the bullet are obviously the fit to the throat and it's location from where it's held by the case. Lots of variables. Lots of opportunity for refinement.
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