Reloading full wad cutter bullets.

[Mike38]

Ammo: .32 S&W Long, reloaded, 98 grain swaged HBWC bullets. Pistol: Benelli MP95 semi automatic target. From what I read on most internet sites, the proper bullet depth is even with or just a few thousandths below case mouth, then crimp the mouth just a little over the bullet.

Okay, that works, but not with 100% reliability in this pistol anyhow. I get an occasional failure to feed. It's not the magazine, I have 4 of them and it happens with all 4. So I tried a little experiment. The cases are trimmed to .910 (.920 being the suggested length) and I leave approximately .005-.010 of the bullet above the case mouth, then "medium" crimp into the bullet. Yes, this distorts the bullet because of the soft swaged lead. But, I shot 100 rounds yesterday without a failure of any kind. 25 yard accuracy is < 1.5 inches, haven't tried 50 yards yet, but plan to. Does anyone see a problem with this? If it works, do it, right? Thanks.

[reddog81]

Originally Posted by Mike38

If it works, do it, right?.

That seems reasonable. Trimming down the case .01 and then leaving the bullet sticking out an extra .01 should result in the same pressure as a regular load. If it works in all 4 without issue that sounds like a winning combo.

I had to Google the gun to see what it looks like. Looks like it’d be a nice shooter!

[FrankenMauser]

Perfectly reasonable, to me.

Half the time (for revolvers), I don't even fully seat wadcutters. I leave a bit hanging out of the case and adjust powder charges to compensate for the increased internal volume after testing.

[T. O'Heir]

98 grain swaged HBWC bullets are pretty much what bullseye shooters have used or eons. "...not with 100% reliability..." You need to use as little crimp as possible.

[Unclenick]

Deforming the nose of a bullet has very limited effect on its ballistics other than to change the ballistic coefficient of pointed bullets for long range shooting. With a flat nosed wadcutter there just isn't any way to make the BC and lower unless you add flaps to it, so imbalance is all that's left as possible damage. You may get a little, but the chances of it being very significant by the time you get to 50 yards seem small.

If I suppose a velocity of 800 fps (a little high) and the standard 18¾" (476 mm) twist, then an imbalance that moves the CG of the whole bullet 0.001" off center will result in about 0.64" of radial dispersion at 50 yards. In other words, it might add 1.28" to the group diameter. But when you consider the crimp is affecting only a small portion of the total length, you might need to achieve 0.010"-0.020" of asymmetry at the crimp to get that much imbalance, and that's more than I would expect you are getting.


How the calculations work:

Where:

v=bullet speed in ft/s
P=rifling pitch in inches
s= time in seconds
R=revolutions
r=radians

Bullet revolutions per second (rps or R/s; not rpm) are:

R/s = 12v/P = 12 × 800 / 18.75 = 512 R/s

To convert R/s to radians per second (r/s), multiply R/s by 2 × pi r/R

512 R/s × 2 × pi r/R = 3217 r/s

Multiply radians/sec by the CG offset to get the lateral velocity off the nominal trajectory

0.001 in./r × 3217 r/s = 3.217 in./s lateral velocity

50 yard time of flight for a 32 WC bullet at 800 fps with a BC of 0.044 is about 0.2 sec.

3.217 in./s × 0.2 s = 0.6434 in. drift off center, or a potential group diameter increase of 1.2868 in.