Are bevel base cast bullets less accurate than flat base

[GSP7]

in .44 and .45 caliber, Are bevel base cast bullets less accurate than flat base with square edge, in your experience ?

Are flat base mold bullets more accurate?

Bevel base like the ones Missouri bullets sells

:Fire:

[Ausglock]

Bevel base 230gn RN are more accurate than I am. flat base are a mongrel to cast without flashing around the base. Makes HITEK coating a chore. Bevel base make coating easy.

[Larry Gibson]

I've done considerable testing of BB vs FB cast bullets of the same design in 38, 44 and 45 calibers. Testing was done in 38 and 44 with revolvers and with revolvers and semi autos, all from a Ransom Rest with target at 50 yards . in every test the FB bullets proved more accurate.

However, I doubt 99.99% of shooters can take advantage of the difference in accuracy.

[lightman]

Its been my experience that flat base are more accurate but I usually can't shoot the difference. Bevel base bullets are a pain to size and lube if you're not using a Star. If you're coating them it doesn't much matter.

[Martin Luber]

Larry nailed it. I would add that FB take special care in handling and loading because if it doesn't seat straight, you wipe a crescent off the base degrading precision. A bored out seater plug seats by the shoulder giving a straight push and proper expansion (plug) of the case so it can insert 1/16th inch first is critical. Hard BB boolets solve problems you didn't know you had. Some dies size the shell too small and the base can get pinched in.

[Rapidrob]

Over 100 years ago, Dr. Mann ( A Bullets Flight From Powder to Target ) book, did extensive test on hundreds of bullet shapes. without a doubt the flat base bullets are more accurate.
I my shooting for the last 58 years, I too have found that the flat based bullet is more accurate at close to moderate distances.
( under 600 yards) for no other factor than drag.
The flat based bullet also enters the lead of a rifles bore in a more concentric fashion as the gases have a flat surface ,rather than a "boat-tail" base which can be pushed to one side causing a misalignment to the bore of the rifle/pistol.
A for cast bullets, I always slightly flair the case mouth anyways to allow a proper seating of the bullet into the case.

[bmortell]

id think a bevel base would magnify any negative effects from your crown since you don't have the sharp corner to corner exit like FB

[megasupermagnum]

I'm told the one advantage to bevel base bullets is that they are easier to get into the case, presumably on a progressive press. For my fumble fingers, this is not the case. Flat base is just as easy (or difficult) to load quickly for me. I've found some bevel base bullets that are very accurate, but as a whole it seems to be that flat bases shoot better. Personally I believe it has more to do with balance, but the actual reason isn't important. There are other disadvantages besides accuracy too.

If I were buying a custom or semi-custom mold, I would NEVER choose a bevel base.

[JWFilips]

I trust Larry's testing but 90 % of us would not see a real difference in every day shooting

[Outpost75]

I'm with JW Flips. Larry is correct, and testing by Col. E.H. Harrison at NRA and published in the NRA Handloader's Guide agrees. However, I find that the bevel-base bullets are easier to seat straight on the Star and Dillon machines and carefully loaded are accurate enough for all but the most severe competition requirements.

I still like bevel base and most of my Accurate designs are.

[GSP7]

Over 100 years ago, Dr. Mann ( A Bullets Flight From Powder to Target ) book, did extensive test on hundreds of bullet shapes. without a doubt the flat base bullets are more accurate.
I my shooting for the last 58 years, I too have found that the flat based bullet is more accurate at close to moderate distances.
( under 600 yards) for no other factor than drag.
The flat based bullet also enters the lead of a rifles bore in a more concentric fashion as the gases have a flat surface ,rather than a "boat-tail" base which can be pushed to one side causing a misalignment to the bore of the rifle/pistol.
A for cast bullets, I always slightly flair the case mouth anyways to allow a proper seating of the bullet into the case.

You nailed it :Fire: I also slightly flair the case mouth to allow proper bullet seating

[bedbugbilly]

I trust Larry's testing as well. The question I don't have to ask is if I'm in the 99.99% he speaks of . . . . I already know I am! :-)

[megasupermagnum]

Some of you have mentioned case flaring. Are there people who don't flare cases? Even with jacketed bullets, how are you supposed to seat a bullet without a flare? The one and only exception for me is a boat tail jacketed rifle bullet.

[ACC]

The 158 grain bevel base .357 FPRN bullet from Lee is very accurate in my Blackhawk. But the revolver prefers the 125 grain FPRN a little, but that bullet is kinda small for feral hogs, but works nicely on feral dogs.

ACC

[GSP7]

Some of you have mentioned case flaring. Are there people who don't flare cases?
That was my thought too

Apparently ....? sounded like someone doesnt....

[smilie=1::Fire::coffee:

.

[gumbo333]

99.9%. I'm finally in the majority on something!

[trapper9260]

I go with Larry said ,He show also the different in long and short boolits for 308 Win and the gas cutting on it. So I take it you will get some with BB then FB. That is how I thinking.But like he said for me I would not see much of a different when shooting.

[Silvercreek Farmer]

Can anyone quantify the difference? 1/2" at 50y? 1" at 50y?

[MT Gianni]

SC Farmer, I am not sure a Ransom Rest or similar would transfer equally to a hand held shooter. IOW, if you normally group 3 " at 25 yards a shooter who groups 1 1/2" would not probably show the same rate of dispersion. A quick review through Cast Bullet matches will show no bevel based designs in rifles winning matches.

[bosterr]

At one time I had both a Saeco 4 cavity bevel base mold and a Saeco 4 cavity flat base mold. both were Saeco's H&G 68/69 versions in .45 and the flat base one was enough more accurate I sold the bevel base one.

[tazman]

In the vast majority of my accuracy testing, the only way I can tell differences in accuracy is from a rest.
Even when the groups from rest are one half to one inch different at 25 yards, my offhand shooting doesn't show any difference in group size.
My point being, such small differences in accuracy are no practical difference for any use of mine.
If you like the boolit design, shoot it.

[megasupermagnum]

SC Farmer, I am not sure a Ransom Rest or similar would transfer equally to a hand held shooter. IOW, if you normally group 3 " at 25 yards a shooter who groups 1 1/2" would not probably show the same rate of dispersion. A quick review through Cast Bullet matches will show no bevel based designs in rifles winning matches.

Unfortunately I do not own a ransom rest to use on a regular basis. I have tested this theory though, and proven that it is relative. If a load X shoots 3" in a ransom rest, and load Y shoots 4", then you hand the gun to a shooter and he shoots load X about 6", load Y will be about 7". To do this requires enough shooting to get an average.


As for quantifying FB vs BB accuracy differences, that is nearly impossible. I will give some examples. A recent test I did in 45 acp, with nearly identical bullets, one FB, one BB. At 50 yards off a rest the BB shot an average 4.8", and the FB 3.4". Another recent test I did found the BB better. In 41 magnum, in comparing the Lee 195 gr swc (flat base) to the 210 gr swc (bevel base). My gun hates the 195 gr FB. I never got less than 6" at 50 yards with it. It seems to really like the BB, and I'm down to about 4" at 50 yards. In this case though, I believe other differences, mainly the front driving band, has more to do with the accuracy than the base.

[Walks]

I've never expanded a bottle-necked rifle round to load J-bullets.
I do expand case mouths for Lead alloy bullets. Either PB or GC

Don't know exactly why it is Lead will shave off a bullet when loaded in a case that has Not Had It's mouth expanded.
Where as a J-Bullet will Not Shave off jacket material when seated in a non expanded case mouth.
All cases having been chamfered & deburred properly.
And I've broken down enough J-Rounds, either FB or BT to know that J-Bullets do NOT shave J-Material when seated.

I do prefer FB to BB regardless if I'm loading single stage or progressive.
For me the flat base are easier to seat straight.

[RydForLyf]

Bevel base 230gn RN are more accurate than I am. flat base are a mongrel to cast without flashing around the base. Makes HITEK coating a chore. Bevel base make coating easy.

I just spent an entire day of working from home cleaning up about 1,500 to get rid of flashing. Total pain and waste of time. Time to ditch plain base mold.

[megasupermagnum]

I just spent an entire day of working from home cleaning up about 1,500 to get rid of flashing. Total pain and waste of time. Time to ditch plain base mold.

It is every bit as easy to have flashing on a bevel base bullet. All that is, is too high of sprue plate temp. Try a mold other than a round nose, and you might be surprised how accurate they can be.

[Outpost75]

FWIW, my .38 Special handloads assembled with the Saeco #348 double-end, bevel-base, 146-grain wadcutter, cast from 1984 FBI-Quantico indoor range backstop lead, loaded as-cast and unsized, lubricated with 45-45-10, in Winchester brass, WSP and 3.5 grains of Bullseye, on a Star machine at 1.20" OAL, using the Redding Profile crimp, averaged under 2 inches at 50 yards firing ten consecutive ten-shot groups from my BSA-Martini action with Green Mountain barrel and 10x Unertl scope. In my 1939 Colt New Service .38 Special from Ransom rest,they do the same for 6-shot groups.

[dverna]

The only testing I did with the Ransom Rest was with the .38 Spl. It was done decades ago. IIRC BB bullets grouped 1/2” larger at 50 yards out of a S&W M52. Bullets were cast from Linotype. One data point is not too meaningful.

For pistol loads, the potential improvement in accuracy is not worth the added frustration. BB bullets seem to drop out of molds easier and are easier to seat.

[onelight]

I have always bought flat base molds because I had heard there was a big difference . But it appears that there is not much practical difference at the ranges I shoot 25 yards or less off hand , and my skill level.

[fatelvis]

Larry nailed it. I would add that FB take special care in handling and loading because if it doesn't seat straight, you wipe a crescent off the base degrading precision. A bored out seater plug seats by the shoulder giving a straight push and proper expansion (plug) of the case so it can insert 1/16th inch first is critical. Hard BB boolets solve problems you didn't know you had. Some dies size the shell too small and the base can get pinched in.

So using a flat based boolit in conjunction with a M-style expander sounds like a winning combo!

[clemje]

Depends on the gun. Depends on the type/quantity of powder. Depends on the boolit itself. Depends on how the load was developed... and on and on. There's a whole lot of "what if's" involved...

It's been my experience that a beveled base boolit will shoot as well as a plain base and vice-versa assuming the load it worked up properly, the gun will actually shoot that style of bullet and if the shooter does their part.

[Taterhead]

I'm not a good enough shooter to notice accuracy differences. I do like how flt base bullets set on cases that have been flared with an M profile expander. The square base mates better with the squared off casemouth flair. Bevel base doesn't locate as positively, but it's a modest preference.

[wch]

The old time Schuetzen boys used cast bevel based bullets for easier loading in all of their chosen calibers with very, very good accuracy.

[mdi]

I'm one of the 99.99% Mr. Gibson speaks about. I read the pros and cons of bevel base bullets, and IIRC it was here when I first stated visiting castboolits.com (2007). A lot of posts about barrel leading from BB, but just as many about clean shooting BBs. As it turns out my favorite bullets/molds have all been flat based, but not based on type of base...

I had a Lee mold for 45 cal TC mold I customized. I "milled" (actually drilled/reamed) the bevel base off and came up with a flat base 235 gr. bullet. But I couldn't tell any accuracy difference between the BB or FB from the same mold...

[kevin c]

My need is to load a lot of boolits to be shot at under 25 yards, at speed, at targets with a top scoring area that is 6" X 11". BB may not be quite as accurate as FB, but for the ease of loading and shooting thousands of sufficiently accurate rounds a month, BB wins hands down.

ETA: Fatelvis, I find the custom M style expander made for me by Lathesmith works wonders with my BB casts. No shaving of the coating, and no sizing down inside the case.

[charlie b]

I'm one of the 99.99% Mr. Gibson speaks about. I read the pros and cons of bevel base bullets, and IIRC it was here when I first stated visiting castboolits.com (2007). A lot of posts about barrel leading from BB, but just as many about clean shooting BBs. As it turns out my favorite bullets/molds have all been flat based, but not based on type of base...

I had a Lee mold for 45 cal TC mold I customized. I "milled" (actually drilled/reamed) the bevel base off and came up with a flat base 235 gr. bullet. But I couldn't tell any accuracy difference between the BB or FB from the same mold...

Interesting. I did the same thing with mine. Mainly cause casting was easier with the FB.

Jacketed bullets do need a 'flare'. The neck chamfer is enough for jacketed. I failed to do that on a batch of cases one time and the sharp edge did shave copper. Went back and did the chamfer and everything was good. If a lead bullet is hard and not too big in dia then they do not need the neck flared. But, normally the cast bullets are a bit bigger in dia so the neck needs to be flared a little.

[Onty]

I've done considerable testing of BB vs FB cast bullets of the same design in 38, 44 and 45 calibers. Testing was done in 38 and 44 with revolvers and with revolvers and semi autos, all from a Ransom Rest with target at 50 yards . in every test the FB bullets proved more accurate...
Are FB boolits bit more accurate than BB because obturation of FB boolit base is more likely to happen than with BB ones?

[mdi]

I flare all the necks of all the cases I reload. I look at it this way; it is much easier to install a .429"-.432" slug onto a .427" tube with some sort of entry way (just using 44 Mag. as an example but applies to all other bullets whether cast, J, or coated). The flare doesn't need to look like a tuba just a few thousandths taper for J bullets and a bit more for cast.

FWIW; my method also helps concentricity of a finished cartridge. My 308 handloads with Hornady bullets loaded in LC brass with a slight flare give me a .0015"-.0025" runout as per my Hornady gauge...

[ascast]

Interesting that most old Winchester molds cast a Bevel Base bullet.; maybe for ease of seating.

[charlie b]

Are FB boolits bit more accurate than BB because obturation of FB boolit base is more likely to happen than with BB ones?

IMHO no.

Even in jacketed bullets the flat base tend to be more accurate at shorter ranges, 100-200yd. I believe it is due to the effects at the muzzle. The flat base has less interaction 'time' with the muzzle where a bevel base or boat tail has a bit longer. Not an issue if everything is running true, but, it means the BB or BT has two critical dimensions, the front and rear portion of the bevel/boat tail, instead of just the one edge of the FB bullets.

PS the boat tail on jacketed is there simply to decrease aerodynamic drag for higher velocity at longer range.

[Forrest r]

More than most likely it's me but it seemed it didn't matter if the bullets were beveled or flat based with standard pressure target loads. I'm talking target loads with wc's in 38spl cases, 45acp swc's or 44spl swaged wc's. When I used hotter loads p+ or 357/44mag's the fl bullets tended to be more accurate.

What's equally as puzzling is the rounded edges of installed gc's don't seem to be affected by the higher pressures loads accuracy wise.

[JoeJames]

Some of you have mentioned case flaring. Are there people who don't flare cases? Even with jacketed bullets, how are you supposed to seat a bullet without a flare? The one and only exception for me is a boat tail jacketed rifle bullet.Wondering the same thing. With cast boolits, unless they have some kind of secret procedure, I of course always bell the case mouth enough to start the boolit. On jacketed I have found just a bit of deburring on the inside of the case mouth is usually sufficient - but there are times I bell the mouth a tad depending on the J-word boolit I am using.