Dedicated bullet designs for PC

[Cole440]

Hey all, since coating with Smoke's PC I have sold all of my lubing equipment and switched to push through sizing. What can I say, Im happy as a pig in shi*! You guys were right not to bother with the HF stuff, at this point im diluting it 50/50 with Smoke "Carolina blue" to make purple and get rid of it.

Anyway, this got me thinking, I don't have very many molds and some of the ones I do have have large grease grooves (think Keith SWC). It seems like the powder is usually thinnest around all of these sharp edges.

I see people like Arsenal Molds sell designs that are grove-less for PC.

Any experience with, or thoughts on these?
Looking forward to the discussion,
Cole

[Traffer]

You can remove grease grooves from molds.

[Cole440]

You can remove grease grooves from molds.

Well, I guess my question is should we do that?

[Charlie Horse]

I would like molds a tad smaller in diameter - to make up for the extra girth the PC provides.
I'm having best results using 9mm molds in my 38's.

[Kraschenbirn]

I've got two of Arsenal's 'PC' molds...a 358-165PC RNFP and a 309-188PC-RN bore-rider. Both have produced first-class boolits from the git-go and both cast their specified diameter +/- .0005 from my alloys and, as such, are easy to size after coating.

Bill

[jcren]

Personally, I pc everything, but do not own a slick sided mold. One reason I started casting was to be more self sufficient in a pinch, and I figure if stuff ever hit the fan, a grooved mold can be lubed with about anything in a serious pinch.

[Cole440]

Personally, I pc everything, but do not own a slick sided mold. One reason I started casting was to be more self sufficient in a pinch, and I figure if stuff ever hit the fan, a grooved mold can be lubed with about anything in a serious pinch.

Yeah you have a point there...

[charlie b]

I also pick std lube designs and then PC. For the same reason.

I am a bit careful about the lube bullet designs. I do not have any with the really deep Keith type lube grooves. I prefer multiple lube grooves. One reason is that many of them work well with Lee tumble lube (45-45-10 or BLL mix). And I have saved enough LLA to lube many thousand bullets :) I also have a batch of Ben's Red lube for pan use (I don't own a lube-sizer).

[insert Boy Scout Motto here] :)

[JM7.7x58]

You want your bullet base to remain as flat as possible. Lube grooves allow the sides of the bullet to conform to the rifling, without squeezing a burr off the back of the bullet.

You may not see the inaccuracies at short range pistol distances. But that burr will wreck your 100 and 200 yard plain base rifle groups.

[popper]

My pistol moulds have shallow lube grooves and I PC them. Lube grooves are the weakest part of the bullet. My rifle moulds (30 cal) have a VERY shallow groove for alloy 'collection' and are PCd. Even the PB ones work fine. IF I don't feel like PC on them, 2 coats of BLL work fine @ hV.

[Smoke4320]

I have both but prefer Lube grove for larger audience resale reasons. As stated if excrement hits the oscillator even fat lubing could get you by

[res45]

I have molds designed for TL, some that are slick sided and some have standard grease groove for both rifles and pistols in multiple calibers and they all take PC just fine, size and shoot as expected with no issues that I can think of.

[Cole440]

Good to know everyone! I am going to transition from my Keith bullets to some more rnfp type stuff. I always had problems with the PC chipping off the sharp edges of that huge lube groove the Keith bullets have.

Happy casting!

[white eagle]

some of the high priced mono metal bullet makers actually cut groove's into their bullets
but they do it for different a reason than lube
so for that reason and others I keep mine with no thought about not having them

[downzero]

Especially for pistol bullets I don't even think it matters. I powdercoat everything and whether a tumble or conventional lube design or whatever, they all come out the same.

[Dragonheart]

Until mold manufactures accept the fact that that there is a large and ever growing market for undersize PC molds, they will continue to manufacture the same oversized molds of the past and herein lies the problem.

When a bullet is cast from a mold it comes out non-concentric (lopsided-not round). This is the physics of the process and has nothing to do with mold quality, alloy or the skill of the caster. To overcome this the bullet needs to be sized to make it round, but only the area where the sizing die touches will be round, the remainder of the bullet will remain lopsided. Lopsided bullets is the reason cast bullet full power loads are not accurate at distance.

But another problem exists when the bullet is sized. For example, a PC 9mm Lugar bullet only needs to be large enough to seal the barrel bore when fired. I have a number of 9mm handguns from different manufactures and sizing .356" works for them all. So if I have a 9mm mold that drops a .358"+ bullet then I add 2 mills of PC I am now sizing down .004". Also simple physics, that metal doesn't disappear, it is moved and has to go somewhere. Lube grooves give that metal a place to go.

[Dom]

I would like to see more tumble lube style molds be made available. All those little narrow groves are excellent in holding PC powder . I bake my bullets standing up. It allows for excellent,even distribution of the powder. It allows for one coat applications, where with traditional lube grove bullets , some times a second coating is required.

[popper]

When you size a lopsided bullet it stays lopsided, metal just moves to a different spot.

[B R Shooter]

When you size a lopsided bullet it stays lopsided, metal just moves to a different spot.

Interesting. So sizing does not make the bullet round, even though it mikes the same all around? What about balance?

[Dragonheart]

Interesting. So sizing does not make the bullet round, even though it mikes the same all around? What about balance?

When a bullet is forced through a sizing die it is made round, but only the area where the die actually touches. If you put the bullet in a concentricity gauge or chucked in an accurate lathe and rotate it the out of round becomes quite obvious.

You are correct, "Balance" is the problem. A lopsided or out of balance bullet at some point will start to wobble and once the wobble starts it only gets worse. This wobble becomes more evident as velocity and or distance increases. For this reason a full power rifle load may deliver very good groups at 50 yards, but look like a pattern at 100. To help overcome this a considerable reduction in velocity has been used.

The only PC cast rifle full power accuracy solutions I have seen that work are swaging the entire bullet or using a bore rider bullet design, sizing the base for the grooves and the nose to the lands. In the latter, by firing the gun barrel is acting as a swage to reform the bullet as it travels down the barrel.

[popper]

An out of round is sized, excess of the out of round gets pushed to the groove so it is still un balanced.