Plain base v bevel base

[Roger Kehr]

I have loaded both types of cast bullet. Other than ease of loading, any positives to the bevel base vs plain base?

[popper]

PB easier to cull when casting.

[GARD72977]

Plain base is supposed to be more accurrate. I cant say I have tested it. I only buy flat base molds......

[ioon44]

I use both types of cast bullets I don't see any difference in accuracy if the bullets is sized to fit the barrel (.002" larger than the bore). Bullet fit is king.

[zarrinvz24]

It depends on what your expected velocity is. If you are running standard loads, <=850 fps, they will likely be very similar. The bevel base makes it easier to seat a boolit without shaving lead. Above standard velocity loads the plain base will come into its own - hot loads will flame cut into the base of the boolit and the bevel base will lead the barrel to a greater degree.

[Bent Ramrod]

As far as I can see, the main advantage is that they tend to fall more readily out of the mould after casting. And thus are better suited to high production setups like automatic casting machines and gang moulds.

I think the sneaky switchover from square to rounded grease grooves in some mould designs was for the same reason.

I’ve never found that either variation improved the shooting qualities of the boolit thus produced.

[ABJ]

I have tested both and can stay sometimes a flat base is better and sometimes a bevel base is better. Case in point, H&R buffalo classic, 30" barrel, I cannot get a flat base boolit to shoot worth crap. A Magma 300 bevel base will cut bullet holes at 100 yds at 1200 muzzle vel.
38 wadcutter loads with the lee 148 bnwc flat base will shoot circles around a bevel base wadcutter. Both of these loads are light for caliber.

I don't think you can draw a hard line on a boolits accuracy based solely on the flat vs bevel argument. Lots of other factors involved, like "ioon44" said boolit fit is a huge consideration, powder choice matched to the alloy is another.

I'll give one more case, a friend gave me some 2000 vintage Laser cast, 45-255-swcbb. Hard, hard hard, my lee tester showed 21 brinell.
My go to load in 45 colt is 5.4 bullseye under my flat base 255. Brinell 14ish I loaded the laser's with the same load and have to admit they shoot a little better in my Uberti break top and mine shot better in my Uberti cattleman. I can't say why. What I can say is I'm confident that I could play around with powder, primers, cases, OAL's and crimps and get either one to shoot as good as the other. So I would not let a good proven design mold get away based on its base.
Tony

[243winxb]

The 200 gr Lyman BB is the most accurate 45acp target load using Bullseye powder for me.

[Burnt Fingers]

The 200 gr Lyman BB is the most accurate 45acp target load using Bullseye powder for me.

I love me some 452630 boolits.

I picked up a 2 cavity just because I kind of collect different 45 ACP molds.

After casting and using the boolit I was hooked. I looked around and found a good used 4 cavity. It's my "main" use 45 ACP boolit now.

It's very similar to the RCBS 201-KT but with a bevel base.

I have a 4 cavity H&G 68. I rarely even cast with it.

[kevin c]

Speed and ease of placing bevel based bullets perfectly upright on the case mouth were the main reasons I went that route, since I need to reload tens of thousands of rounds yearly. That was with standard case mouth flaring; now that I have an M style expander that may change.

My application is not demanding of accuracy, so I don't know that FB vs BB makes a practical difference for me, especially since I tumble the casts, made of BHN 11-12 alloy, multiple times together in coating them, and the base edges just don't stay sharp and crisp.

[45DUDE]

I bench shoot every week with pistol and lean in the flat base section for being accurate. If you have a good mold is a +. With some molds you can look at the base of the boolit and the bevel isn't round. Then again when the boolit leaves the barrel it is grooved up. I run my lead mostly on the hard side. I had some bevel base .430 boolits 240 grain that I didn't like and found I could fit a 41 caliber gas check with my 450 sizer and they were more accurate.

[45DUDE]

The 200 gr Lyman BB is the most accurate 45acp target load using Bullseye powder for me.

Those are pretty. The one on the left and #3 are my favorite bench shooters. A lot of 45's will not function properly with #3. My best 10 shot group is the #3 style but weighs 200gr. with a H&G mold. I like a single grease groove.

[gwpercle]

Plain base may have an edge with heavy magnum and +P loads .
I've tested 38 special , 45 acp and 9mm Luger with BB side by side with PB at the target range , shooting at NRA Bullseye Targets ,indoor , 25 yards , from a rest and really didn't see a marked difference in lighter target type loads .
You need to be a great shot to tell a accuracy difference ... was hoping/expecting to see a day and night difference but all the groups were about the same .
Good sights and a good trigger pull made the most difference in how a gun grouped ... BB or PB didn't seem to matter much at all .
Gary

[rbuck351]

I had a bb 200gr 45 mold for my 1911. It shot as well as other fb molds I have but I didn't like the bb much as my Lyman 450 filled the bb part with lube. Then I got a Star sizer and no more lube in the bb part.

[Bkingnsmth]

Bent ramrod
You are quite correct. Bevel bases are for high production machines. They fall out easier than plain bases.


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[kevin c]

Bent ramrod
You are quite correct. Bevel bases are for high production machines. They fall out easier than plain bases.

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Almost all my molds (aluminum 5 to 8 cavity) are BB, and most of them have a sticky cavity or two. I haven't cast the two or three FB molds I own, are you saying they always stick, or have I just had bad luck or bad technique with the BB molds?

[GARD72977]

Almost all my molds (aluminum 5 to 8 cavity) are BB, and most of them have a sticky cavity or two. I haven't cast the two or three FB molds I own, are you saying they always stick, or have I just had bad luck or bad technique with the BB molds?

PB can cast easily. The straight edges just do not release as well as a edge with a slight radius. Lube groves cause the same issues.

I have PB molds that drop great. A good mold will usually have a sweet spot with heat where the bullets just fall out.

Casting machines favor a bevel base because a stuck bullet causes more problems.

[GARD72977]

PB is inherently more accurrate because it gives the bullet a longer bearing surface. This may mot show up in your Ruger GP 100 @ 25 yds.

When rifles are shot for accurracy its with a PB bullet.

[Roger Kehr]

Thanks for the input guys!!

[DonHowe]

In rifles. And higher velocity revolvers I want flat base. In standard velocity auto pistols I don't think it matters other ease of starting bevel base in some situations. As for accuracy, with standard velocity pistols, if the bullet fits and the load is good, a much bigger factor in accuracy than FB or BB is the nut behind the butt.

[Mal Paso]

Bevel bases are positively a PITA with RCBS and Lyman lubesizers. LOL

Star sizer, no problem.

[greenjoytj]

Does the Star sizer have a valve that only opens to flow lube after the bullet fully down in the sizing die?
Some type of valve or gate to turn off the pressurized lube flow or de-pressurizing the lube tank while the bevel base gap is passing the lube ports.

[Roundball]

The Star Sizer is a wonderment. As to the way it works there is little if any similarity to a Lyman type lube-sizer. This may be a cop out but I'd suggest Googling the Star. That's the way I went getting my antique Star going. A picture is worth many words.

[megasupermagnum]

Does the Star sizer have a valve that only opens to flow lube after the bullet fully down in the sizing die?
Some type of valve or gate to turn off the pressurized lube flow or de-pressurizing the lube tank while the bevel base gap is passing the lube ports.

A Star sizer is an upside down grease gun. A spring or air cylinder puts pressure in the reservoir to feed the lube into a chamber, but does not have enough pressure to do anything except get a tiny dab of lube on the bullet nose, which you often read about. This can be mitigated by lowering the lube temperature, and pressure if you have the air cylinder. What actually does the real lube pumping on a Star, is a piston, which is pushed when the handle is almost bottomed out, it pushes a linkage bar, which pushes the piston. You set the depth of the bullet punch, so that the lube groove or grooves are centered over the die's holes. In theory, lube is only applied when the bullet is in the die, and holes in the die centered over the grooves.

You contrast that with a Lyman or similar down and up style, which the lube is under full pressure the entire time. If there is ever not full contact with the die push rod, or bullet, you make a huge mess.

[DonHowe]

Dies I bought from Star came with lead shot pellets which were used to plug all holes except where you wanted the lube to come out. Plugging holes combined with top punch adjustment aligns the lube groove with open lube holes in the die at bottom of the handle stroke. Then as the handle bottoms the lube is pumped into the lube groove. So lube only goes where you want it.
If I had trouble with lube around bevel bases it would be due to too hot lube and too much pressure. Use of lube which did not require a heater mostly alleviated these problems.

[Mal Paso]

With a Star, misalignment of the groove with the holes puts lube on the nose of the following bullet.

I just wanted to point out to point out to those just starting that bevel bases can be less then fun in certain lubesizers. There are fixes but better to avoid the problem.

[Roger Kehr]

I have found that it does take some time to set up the Star properly. If grease grooves are misaligned, it is a mess. Best practice for me has been to measure to the grooves and set the sizer punch from that...saves a lot of time.

[Walks]

I prefer plain base. I've found that contrary to the experience of others, plain base load easier and straighter for me.

The Lyman #452488 and RCBS #45-201-KT group better out of 2 Colts and a Springfield for Me.
My Dad shot the H&G #68FB for many years in Bullseye Competition.
I guess I've just inherited His preferences.

Someone on this sight that I have an Enormous Amount of Respect for has had a different experience.
Just goes to show that what works best is up to that individual.

[Outpost75]

In my experience a slight bevel base reduces "cupping" of the base in heavy loads, and reduces leading, because you avoid the thin wire edge of a sharp corner being exposed to the hot powder gases, which has less heat capacity than a bevel base. Also, when loading throat-diameter bullets of diameter larger than barrel groove, a bevel base less less likely to drag a "fin" off the corner of the base when being extruded into the tighter barrel. A perfect case-in-point being a Colt Python with typical .3585-.359 cylinder throats and a .354-.355 barrel.

My Accurate design molds have only a minimal 0.03" bevel, which is entirely obliterated by the time the bullet exits the bore, so there is zero aerodynamic difference. I use only tumble-on, film-coating lubes such as 45-45-10 or diluted Lee Liquid Alox, so I don't worry about having to wipe excess lube off the bases.

The bevel IS easier to load in progressive machines without base deformation and drops from gang molds more easily and with less potential for damage than dropping hot bullets with sharp square bases onto others in the pile...

I've shot 100-round comparisons of bullets of both types from heavy test barrels with Unertl scope in .38 Special. If bullets are otherwise from the same heat of alloy, with good fill-out, same weight, profile, diameter and test barrel or revolver cylinder throat fit, being loaded the same, I have found NO statistically significant difference in T-testing samples of mid-range target loads.

Ten-shot groups under 2 inches at 50 yards are the norm for wadcutter brass loaded on a Star machine with 3 grains of Bullseye, 452AA or WST and profile crimped in the Redding die, using a bullet of 146-148-grain weight and single grease groove with double-end, bevel base profile with crimp grooves on each end similar to the Saeco #348. Loading bullets with sprue-cut forward DID make a difference! Bevel-based bullets also retain accuracy more effectively in "full-charge" wadcutter loads at +P velocities and pressures in .38 Special, at which base cupping may occur in softer 8-10 BHN alloys. Grouping of full-charge wadcutters is every bit as good as lower velocity target loads as long as velocities remain subsonic to as to avoid transonic buffeting as velocity decays at 50 yards and beyond. In a fast-twist one turn in 10 inch PPC gun you can get impressive results out to 100 yards or more. Not possible in your 18-3/4" twist S&W.