Another rookie question

[desteve811]

Whats the purpose of a hollow base bullet? pros/cons?

[405]

I'm still unsure of the benefits for some bullets/applications but the theory was/is that expansion of the hollow base can take the place of inertial obturation and allow the pressure of the burning powder charge to expand the base area thus filling out and sealing the bullet base/shank against the bore walls.

Common to the under bore sized minie ball-black powder combos for quick loading in fouled bores. Usually best with relatively light BP loads. I guess that is the pros.

The cons- a point can be reached depending upon thickness of the hollow base walls where the pressure of the charge can distort or even blow out the base destroying accuracy. Lyman has some pretty good high speed pics of this happening as the bullet leaves the muzzle. Looks like a flared shuttle cock :)

[2ndAmendmentNut]

Waning this may be incorrect history, but it is how I learned it.

When rifling was first caught on in muzzleloaders they were more difficult to reload then smoothbores because in order to take advantage of the improved accuracy the ball had to be oversized. Hollow base boolits had the advantage of being a little smaller in diameter, resulting in easer seating of the projectile. Yet upon ignition the HB expanded to fit the rifling, yielding great accuracy.

In modern day boolits like the 38 HBWC the HB is intended to do the same purpose, expand to hug the rifling better. I have heard that if you push a HB boolit to fast, the base will expand so much that it will actually tear away from the base of the boolit and leave a doughnut of lead in your barrel.

[44man]

All perfect answers.
I played with a lot of muskets for friends and found poor accuracy at 50 yards using under size Minnie' balls. Some would not hit a huge paper target. By lapping the molds for a good thumb push fit we were able to hit the 200 meter gong. Moderate charges were needed, about 50 gr. Increase the charge and you could hear the shuttle cock go off into the wild blue.
It was amazing how long it took the thing to get 200 meters! [smilie=1:

[waksupi]

When rifling was first caught on in muzzleloaders they were more difficult to reload then smoothbores because in order to take advantage of the improved accuracy the ball had to be oversized. Hollow base boolits had the advantage of being a little smaller in diameter, resulting in easer seating of the projectile. Yet upon ignition the HB expanded to fit the rifling, yielding great accuracy.

I

I beleive it is more to the point, that they didn't use patched balls when rifleing was first introduced. Balls were pretty much driven down the bore by brute force. Patching the ball came around, making things much easier. I do not believe that hollow based elongated bullets were developed until fairly late.

[Wayne Smith]

Patched round ball goes back to the early to mid 1700's in this country, pre French and Indian wars. The elongated unpatched bullet was being experiementd with in Europe in the early 1800's with various ways to enlarge the base of the bullet. Early experiments used a plug, the break through was the discovery that a hollow base would accomplish the same thing with much less cost. Realize that breach loading experiments were going on at the same time, removing the need to load through a fouled barrel. A lot was being done over a relatively short time.

[Larry Gibson]

Additionally the HB is used to maintain the external dimensions and a given weight of the bullet with different alloys. This is evidenced in the M1873 and M1882 Frankford Arsenal 45-70 service bullets. The HBs in both bullets are not there to aide in obturation as many incorrectly believe.

Larry Gibson

[TAWILDCATT]

the frenchman MINIE developed the bullet with an iron plug.when we used it in the civil war we dropped the plug. The rifle used a heavy charge of BP.hence could shoot 1000 yrds.YES YES.
the modern hollow base in 38 was for same reason but the charge was light.it was mainly used in the S&W 52.lyman does not even list the WC solid.

[2ndAmendmentNut]

Additionally the HB is used to maintain the external dimensions and a given weight of the bullet with different alloys. This is evidenced in the M1873 and M1882 Frankford Arsenal 45-70 service bullets. The HBs in both bullets are not there to aide in obturation as many incorrectly believe.

Larry Gibson

I always thought that that is what the HP (hollow points) were designed for not the HB (hollow bases). Then again I have been wrong before.