Bevel Base vs. Flat Base

[Cadillac Jeff]

Same here

 

[popper]

Primary effect is at the muzzle and gap in revolver, where Bernoulli comes into play. BB will reduce gas fps faster than FB, area of opening (and angle of exit decreases) increases more quickly. As gas fps is 30% higher than bullet muzzle fps, goes supersonic in most cases.. Like popping a champagne cork. A sharp FB edge can be gas cut more easily.

 

[STIHL]

I’m voting C, I don’t think there will be a great enough difference to matter. I plan on testing the theory one of these days out of a ransom rest with 5-6 different WC designs I have and one single load. Still casting bullets for that project. It’s way on the back burner, but I am going to try it.

 

[dale2242]

I vote C.
I have seen no difference in accuracy between flat base and bevel base.

 

[JWFilips]

I'm not the best pistol shooter so my vote is "C " I can not tell any difference

 

[HHD WV]

I can’t see any difference in the shooting between bevel base or flat base. Bevel base is a PITA with Lyman or RCBS Lube sizers. With my Star lube sizer, no problems. I find they seat in the case a bit easier when reloading cartridges. I like bevel base bullets very much. Harles

 

[Bazoo]

I have never seen a difference in accuracy; this was because I did not test rigorously enough. Fortunately John Zemanek answered this question in a 1993 article in Handloader magazine. Using two identical 148 grain Hensley and Gibbs #50 38 wadcutter molds, one plain base the other bevel base and identical target loads, John fired 2600 rounds in three revolvers using a Ransom Rest. Bevel base bullets gave groups averaging 18% smaller than plain base bullets in all three revolvers.

This is a significant difference, but it is 3/16 inch at 25 yards and 3/8 of an inch at 50 yards. When groups are averaging around 2 inches at 50 yards, any improvement this small is hard to detect with the normal variation in group size. It takes a lot of careful testing to show it. No wonder I was not able to see it comparing a few groups.

Does John’s work completely answer the question? No, the difference was small, the loads were light, and the guns were high quality. Different gun, and load will certainly affect the result. If you are competing, using match grade guns, and a tiny improvement is important, I would go with a bevel base.
For most shooting either base style is OK.

Thank you for sharing that information and the source.