bevel base vs plain base

[luvtn]

Hi,
I am fairly new to reloading. Not casting yet, but I have saved brass and scavenged wheel weights for 20+ years. Ya know something to do in my "old" age. I was of the impression that accuracy and fps were a product of obturating the bore. So teach me how a bevel base does this better than the plain base? In other words I am trying to figure out what to buy in terms of a mould. I reload .38, .357, .44 spcl, and .44 mag with cast lead boolits I beg, trade, or buy.
Thanks
LT

[mooman76]

I don't believe it does in fact as far as I know, it causes leading easier which means poorer accuracy. What it does is load a little easier (like the boat tail) because of the angle acts like a wedge and goes into the caseneck easier. I onlt have one mould of that discription and have yet to actually load some of those.

[fryboy]

i see ermm hear from both camps , some swear by it some at it ...i myself like the bevel bases ...as far as shooting and loading goes that is , what i dont like about them is the lubing , IMHO this is where a star luber would be nice as it's about the only way i know where one doesnt get lube on the bevel requiring a wiping off of , most folks i read seem to state that the flat base is more accurate , i've had so few that i could compare side by side that i cant say , by side by side i mean same profile but the only difference being the bevel vs. the flat base , i suppose in part bevel will be subjective a wee one to a large one , i do have several molds in the same weight but a different profile , both in 45 and 358 ,properly sized and lubed i cant tell which is more accurate [shrugz] for me velocity has much more to do with it and some of my most accurate loads are lite ones , of course ur mileage may vary

[deltaenterprizes]

Most guns and ammo shoot better than the hand holding the gun and you will only see a difference if you put the gun in a rest.
The quality of the base ( the lack of imperfections) is the most critical aspect. The bevel base is popular with reloaders because the case mouth does not have to be opened as much to start the bullet, this does not work the brass as much, resulting in longer case life.

[lwknight]

If you use a sizer like the Lyman 450 or similar style the BB bullets are a royal messy pain. The lube gets under the bullet because of the BB.

[HammerMTB]

Early on I fell under the spell that BB boolits weren't as accurate as PB boolits. I cut the BB off my .40 cal gang mold, thinking I was "fixing" it. The result- no change in accuracy AT ALL. Now, if you shoot something that presses the boolit to more like rifle velocities, you might be better off with a PB design. To my way of thinking, that is where the gas check comes in.
So my input into this is that the base of your boolit needs to be even and consistent all around, whether BB or PB. When you have that, accuracy will be fine either way. I will agree that the PBs are easier to lube. That said I have developed my pistol boolits to the point that I can TL them, so the base shape no longer matters. [smilie=w:

[canyon-ghost]

All that would depend on how far you plan on shooting them. I do a lot of shooting to 100 meters so, the plain base or gas checked is usually the way to go. If you're loading tons of defense bullets for 15 yards, or even 50 meters, a bevel base could work. I have one in nine millimeter that's a hollowpoint, it's not bad. I like the hp just fine.

[fecmech]

I have done a lot of shooting with the Lee 9MM 121 tc bullet which has a bevel base on it in my K-38 and 3 .357 rifles, it is very accurate out of all of them. At 50 yds out of the K-38 it will group under 2", out of the rifles it runs about 3-4"@100 yds and is stable and accurate out to 200 yds. I bought an RCBS 124 cn mold because it was an almost identical bullet without the bevel to try. Accuracy is the same between the Lee 6 cav BB bullets and the RCBS PB 2 cav out to 200 yds as near as I can tell. I'm going to do some more testing now that my summer projects are done but so far I can see no difference and I get no leading with either one..

[44man]

Removing the BB from a .357 Lee boolit cut groups in half. I can't say more.

[geargnasher]

Early on I fell under the spell that BB boolits weren't as accurate as PB boolits. I cut the BB off my .40 cal gang mold, thinking I was "fixing" it. The result- no change in accuracy AT ALL. Now, if you shoot something that presses the boolit to more like rifle velocities, you might be better off with a PB design. To my way of thinking, that is where the gas check comes in.
So my input into this is that the base of your boolit needs to be even and consistent all around, whether BB or PB. When you have that, accuracy will be fine either way. I will agree that the PBs are easier to lube. That said I have developed my pistol boolits to the point that I can TL them, so the base shape no longer matters. [smilie=w:

You about covered it! My experiences as well.

Gear

[Larry Gibson]

I found through extensive testing that FB cast bullets in handgun cartridges are always more accurate than bevel bases cast bullets, especially those with large bevels. Yes I have put the handguns in a Ransom Rest. I shoot BB'd bullets only when they are given to me and when there is no other mold available. It does require a handgun and a shooting platform to tell the ifference. Some shooters can. I first became aware when I was shooting the old FB H&G 68 in my match M1911 and a very nice M25. When I switched to the newer BB H&G 68 accuracy doubled. I tried several of the H&G BB moulds and accuracy was the same, worse than the FB H&G 68. I also knew this from my PPC days when my groups at 50 yards with BB WCs wouldn't hold the X ring any more. Testing in the Ransom Rest showed that the FB'd bullets just palin shot better.

Mostof the "reasonsing" for the use of FB cast bullets is; they feed better in auto matic presses and they drop out of machine casting moulds better. Neither of those reasons is any good to me. I prefer the accuracy over a commercial castors convenience and I don't have an automatic bullet feed anyway. The FB' bulets load just fine on my SDB and 550B and they shoot better. That's my choice any one else is free to use BB bullets if they want to.

Larry Gibson

[Uncle Grinch]

I agree entirely with Larry's comments and have experienced issues with accuracy in my 45 Colt using BB. I eventually sold it off.

[geargnasher]

I'll throw something else into the mix: It has been my experience that two-groove pistol boolits shoot better than single-groove boolts, expecially in large calibers. Funny thing is, look at how many grooves BB boolits usually have. If you can cast a BB boolit as well as a PB boolit, you might have to have a ransom rest to tell the difference. Don't get me wrong, I used to hate BB boolits and still aren't in love with them, but they can be made to shoot almost as well as PB and for many of us there isn't a discernable difference. I just didn't want to see a bunch of people suddenly get the idea that BB boolit designs are total junk and thus artificially limit an already small universe of moulds.

Gear

[Larry Gibson]

Gear

My below par scores in PPC and IPSC matches when I switched to BB'd cast bullets did not require a Ransom Rest to tell me what the difference was. When I switched back to FB'd cast bullets my scores went back up where they were, especially on the PPC 50 yard line, I then knewwhat the difference was. My hits on small game also went back up when I quit using BB'd bullets in my hunting revovlers. It convinced me bu then I may have been a little more demanding than most who are satisfied with BB'd bullets.

Larry Gibson

[luvtn]

Thanks for the input. I have shot both the bb and the fb. Out of my sp-101 at 15 yds I can't tell a difference. At some point in time I want to buy another gp-100 for hunting. I think I;ll get the fb so I won't be potentially dissappointed if I miss a deer. On the other hand it might be nice to have an excuse for Missing. Ha ha.
lt

[Recluse]

My below par scores in PPC and IPSC matches when I switched to BB'd cast bullets did not require a Ransom Rest to tell me what the difference was. When I switched back to FB'd cast bullets my scores went back up where they were, especially on the PPC 50 yard line, I then knewwhat the difference was. My hits on small game also went back up when I quit using BB'd bullets in my hunting revovlers. It convinced me bu then I may have been a little more demanding than most who are satisfied with BB'd bullets.

Larry Gibson

Ok, this is a first.

Larry, you are one of the mentors from another thread that I mention I learned so much about casting from. Going way back to the beginning here, your posts were ones that always made me sit up and take notes.

As a general rule, I don't care for bevel-base boolits or boat-tail j-bullets in my higher-velocity caliber rifles. My Sierra and Speer plain base 150 grain .308 j-bullets still give me .75" groups/100 meters in my beloved Savage 110B 30-06. The new age boat-tails can't seem to do that.

But in my .45 ACP handguns (old Gov't Mod 70 from my service days, Series 70 Gold Cup, Sig P220 and my beloved AMT Hardballer Long Slide), hands-down, bar-none, no questions asked number one boolit is that Lee bevel-base .452200SWC. I can tumble-lube that boolit, which I often do, in my 45/45/10 blend and that boolit--even with a variety of different powder charges--just flat rocks my world. Nowdays, I use a concoction of beeswax, JPW, LLA and stearate in a stick lube in the lubesizer for that boolit. Results are other-worldly.

In fact, it's the one boolit that leads the least in my old Gov't model Colt--and that gun will lead up if I even wave it near a bucket of wheel weights. :) Out of the Long Slide, that BB200SWC is ungoshly accurate. I've shot informal bowling pin matches with that combination, and it's virtually unbeatable.

In the Gold Cup, it is the best boolit I've ever shot.

Now, me and my .45's, we have a thing with each other and I'm as comfortable with a .45 auto as a person can be and my wife and daughter are always commenting that those .45's look like they're just a natural extension of my hands and that they're the only guns I own that when I handle or holster, look like I'm not even handling a gun because they're such a natural extension of my body.

So my experience with bevel-base .45 caliber boolits is different than yours, at least with that one particular BB boolit. I've tried the plane-base boolits from Lyman and RCBS molds and while they shot superbly, they couldn't compare with this little inexpensive Lee two-cavity bb-base mold.

I've also used that same boolit to make some light loads and plinker loads for the Taurus Judge with the 3" barrel. Same thing: Best accuracy out of all the boolits I've tried with that particular (and notoriously UNaccurate) firearm.

Now admittedly, running them through a lubesizer is a royal pain and time-intensive process. If anything will ever convince me to get a Star lubesizer for a single caliber function, this particular boolit will. :)

:coffee:

[azcruiser]

don't think on is better than the other in so far as accuracy goes but I could be wrong.I do know
a sure way to increase you accuracy and that is practice,practice,practice. Anybody can buy a high dollar race gun and look good or a custom bench rest rifle with one of those fancy barrel.
But the top shooters that I know swear that practice is the key

[Bret4207]

Obturation is a by product of pressure. It sometimes leads to increased accuracy/fps by forcing the boolit to fit the bore/throat and blocking escaping gas. It can be a blessing or curse, I tend to lean towards the latter.

IMO the BB is theoretically just as accurate as a similar design of the FB variety. But, I have not found BB to be as accurate over the long run, at least in the designs I tried. I have read of people who theorize that a BB allows the pressure to "run to the side" or to otherwise be forced away from the base. While I don't pretend to understand how gases react under pressure, I'm told they are similar to fluids under pressure and that tells me the pressure should be equal across the base- until it finds a place to escape through. If someone with a background in a field that uses this stuff tells me I'm all wrong, I will be more than willing to listen respectfully. But based on my laymans experience with hydraulics it seems to me the pressures should equalize regardless of base design using common style bases.

One thing I have noted in casting BB designs is that it's sometimes hard to tell if your base is perfect. IOW, with a FB you have a nice 90 degree edge and you can see/feel imperfections. I have a BB mould that gave poor results, a 45 of 200 grains IIRC. I eventually figured out my BB was uneven. With a BB you don't have just one "corner" or "edge" to the base, you have 2 which to my mind increases the chance for imperfections by twice at least. Again, maybe I'm over thinking things, but IMO absolutely perfect bases are even more important with BB designs and that much harder to check.

Just ny 2 cents and worth just what you paid for it.

[Daryl]

I use Lee 6- cavity molds. The BB is a pain in the Lyman 4500 lubesizer s others have said. I had a friend mill the bevel out of a 2-cavity mold and they shot fine. Just holding the gun myself on a target with 10-20 shots each, there was a noticeable improvement with the PB. And, the lubesizing is a breeze without that bevel to contend with.

I had all my 6-cavity milled down too. If I could purchase them at Lee pricing that way, I would.

Good luck.

PS If I could find a Star and did not have the investment in dies and punches that I have in the Lyman, I'd go that route.

[Three44s]

Bevel based boolits simplify loading. I do/have shot commercially cast BB slugs and get by with less case mouth belling.

All my molds are FB's however.

I would not completely avoid a BB design but would buy it with the intent for a dirt buster and less for serious target work.

My best looking mold is a RCBS 250K ....... and that sums up my thinking.


Three 44s

[Larry Gibson]

Recluse

Your results with the Lee TL bullet is not unusual. However, That Lee bullet has a very, very small bevel (at least with my Lee mould) which is not anywhwere near what the Bevel is on most commercial cast of the Lee 452-200-SWC (close copy of the new H&G 68) for example. On my Lee 452-200-SWC the bevel is so pronounced I can actually crimp a GC on it (shoots very well that way!). There is not way to get the GC on the TL bullet. Another example of a small bevel based bullet shooting very well is the Lee 356-120-TC which also has a very, very small BB. Yet it does shoot extremely well. However, if I use a commercial cast bullet with a larger BB they do not shoot near as well.

I havefound the TL452-200-SWC to be a good bullet but I picked up a Lee 452-190-SWC, which is a FB bullet, and it shoots more accurately than the TL in my 3 .45 ACPs, my M1917/25 revolver, my .45 Colt Uberti SAA and my M92 rifle. Not a lot more accurate but still consitently more accurate.

That is why I said (in my origianl post). "FB cast bullets in handgun cartridges are always more accurate than bevel bases cast bullets, especially those with large bevels". The bevels on both of the Lee bullets , 356-120-TC and TL452-200-SWC, are almost non existant when I size them. I suspect on exit from you barrel there is very little, if any, of that small bevel left. There are always "exceptions" in this game but the reasons are usually there if we look. It is essentially then a FB'd bullet and shoots well. However, don't take my word for it, sometime try some commercial H&G 68s with the large bevel and you'll quickly understand what I'm saying. I'm not insinuating that you should dump the Lee bullet that obviously is working for you BTW. Always good to hear from you.

Larry Gibson

[fecmech]

Removing the BB from a .357 Lee boolit cut groups in half. I can't say more.

I also did that in 2 cavities of the Lee 6 cav I mentioned in my post, the bullets shot no better than the ones with the bevel. As Larry mentioned in his post that bullet has a small bevel, that may be the reason.

Larry--I also shot PPC in the distant past and played with Ransom rests. The only cast wadcutter that shot well enough for me to compete with was the H&G #50, it would hold the X ring at 50.

[Recluse]

Recluse

Your results with the Lee TL bullet is not unusual. However, That Lee bullet has a very, very small bevel (at least with my Lee mould) which is not anywhwere near what the Bevel is on most commercial cast of the Lee 452-200-SWC (close copy of the new H&G 68) for example. On my Lee 452-200-SWC the bevel is so pronounced I can actually crimp a GC on it (shoots very well that way!). There is not way to get the GC on the TL bullet.

Larry Gibson

You are EXACTLY right. . . I just went out to the shop and grabbed a handful of those Lee boolits--and the bevel is very slight and definitely not nearly as pronounced as some commercial cast bullets I still keep around for comparison's sake.

This (Lee) boolit is not a tumble lube, but rather has the single lube groove that is relatively deep for a Lee design. Most Lee boolits seem to have rather shallow lube grooves.

I'm guestimating that one reason this particular boolit may work so well for me is that because of the slight bevel, less brass manipulation has to be done in terms of flaring, and the taper crimp (that I use on all auto-loading rounds) "blends" into the overall cartridge profile easier, making it so that I get a more consistent round with each pull of the (reloading) press handle.

This is all pure speculation on my part, as I'm more the right-brain (creative) artist type when it comes to casting and reloading, whereas you and Bret and Ian (Geargnasher) are the scientists (left-brain facts and provable logic). :)

I know what works for me and what doesn't--most of the time I don't have the slightest clue why, though. I've learned more from you and the other original members here about the "why" than I ever thought my brain was capable of grasping.

:coffee:

[Larry Gibson]

Recluse

Another excellent 452 bullet in all of my .45s is the 452-200-RF. Intended as a "cowbboy" bullet it does very excellently in the ,45 ACP also and feeds in everything. I had a major brain fade and only got a 2 cavity, probably need to rectify that with a 6 cavity one of these days. Always good talking with you.

Larry Gibson

[geargnasher]

Bret, according to what I remember from General Inorganic chemistry, you're understanding of how gas under pressure behaves in a dynamic system is correct.

I also bet that, if you were to take a shining example of the BB boolits you have good luck with and compare those with an example from someone who says they don't shoot worth a hoot, there would be slight but important differences in the quality of the BB fillout, or perhaps the BB is easier to damage along the all-critical "base" band when seating in a case. I'm not saying BB shoots as well as PB as a rule, I don't think they do, but I think it is more a casting/loading issue than an inherent design issue.

Gear

[Char-Gar]

I am not a science type, nor do I enjoy Internet debate. I am just an old crotchety silver haired caster and shooter of pistol bullets. I would have to do allot of math, but I have well over a half million rounds cast, loaded and shoved down various handgun barrels over the past half century. I have made every mistake that can be made.

That said, I would not waste money on BB pistol bullet molds. They are a general PITA to lube and load, but don't improve accuracy, nor reduce leading. They do reduce the need to bell the cases just a smidge, but that is the only good thing I can say about them.

The principal benefit of a BB mold is realized by a commercial caster who uses the automated casting machines. The BB bullets fall from the molds far easier than the PD do and speeds up production and in business time is money. Other than that, there are no advantages over PB bullets only disadvantages.

[geargnasher]

Actually, bellmouthing less with BB boolits may be part of their bad rapp. Again, I agree fully that there is no real advantage, only disadvantages to using BB designs, but if you under-bell the case and use the base to partly force it's way in, there could be a base deformation issue right there, especially if the boolit isn't started perfectly straight in the case.

Gear

[lwknight]

My best and most accutate boolits for 38s in a GP-100 were gas check SWCs without the checks. Go figure..
I figured that a GC design boolit w/o the GC would equate to a BB.

[Bret4207]

Bret, according to what I remember from General Inorganic chemistry, you're understanding of how gas under pressure behaves in a dynamic system is correct.

I also bet that, if you were to take a shining example of the BB boolits you have good luck with and compare those with an example from someone who says they don't shoot worth a hoot, there would be slight but important differences in the quality of the BB fillout, or perhaps the BB is easier to damage along the all-critical "base" band when seating in a case. I'm not saying BB shoots as well as PB as a rule, I don't think they do, but I think it is more a casting/loading issue than an inherent design issue.

Gear


Agree. As I said, I've never found them to shoot as good as FB over the long run. You might have my posts confused but I found the BB itself on my inaccurate designs having uneven fillout and "wavy" edges. Hand to resort to a magnifying glass to figure it out.