Mold question- straight wall/no lube groove molds for PC?

Been lurking for years, but ready to get the ball rolling on casting. I've been collecting "stuff" for quite a while and over time it looks like things have changed (mainly powder coating vs lube). So I have some questions about buying molds that don't have lube groove (Straight wall? correct me if there is a correct terminology here).

My plan is to powder coat all cast bullets I make. The bulk of my uses will be heavier bullets shot at subsonic speeds suppressed. I have a few molds currently but since I am starting to look at new molds, should I mainly be looking at "custom" molds (NOE, MP, Accurate) that I can order without any lube grooves since I plan to powder coat the boolits? Same question- I assume I should be ordering without gas checks as I won't be pushing them hard.

For example, I bought a Lyman 457406 (480gr gas check) a while ago and just got a new 45-70 Dark (typical for me, I knew i would get a 45-70 one day and when I saw the mold for sale locally I bought it, way before I actually had a 45-70 rifle), but now that I have it and starting to develop loads for it (subsonic with a can), I can't help but looking at some straight wall molds in the 500gr range (HP possibly, straight wall, non gas check) to use instead. Is it worth buying another mold that fits more in what I have in mind?? (yes I understand the group I'm asking!)

I have a few other "traditional" molds already and will try them before I start to buy new ones (Lee 44 mag 240/300gr molds, a custom 110gr 6.8spc mold, Lyman 311359 for 30 carbine, NOE 311-247gr).

Same question about straight wall molds in other calibers I'd like to have molds for (if they are even available)- 35rem, 348 win, 22 hornet/bee mold, 32-20, and a few basic pistol calibers (9mm 147-160gr, 38 158gr, etc).

Is there a reason/benefit to sticking with traditional lube groove molds vs no lube groove molds if I plan to powder coat everything? Will one shoot better than the other?

Not sure it makes a difference but will be sizing with the Lee APP press and have a few sizing dies for it so far. I do have a Lyman 4500 and sizers for that if needed. I do have 6.8, 35, 44 and 348 gas checks (buying stuff when I saw them on sale over the years).

Sorry for the questions, I looked back a few months and read a bunch of stickies in the forums but maybe I wasn't looking in the right place!

I have found no lube groove molds to be slightly less accurate, especially in plain base form. With no groove for displaced metal to move to, the recovered plain base NLG bullets show a skirt at the base of the bullet where lead gets drug down the side and a hollow base forming from pressure and friction on the driving band. A slight bevel base or a single tumble lube groove gives this metal a place to go. I got best accuracy with NLG molds shooting non-oversized bullets.

Like monometal (think all copper) bullets have grooves to lessen the rifling engraving friction the grooves on the cast bullets actually reduce the friction of the bullet. The old timers used plain sided bullets but wrapped them in paper, called paper patched bullets. Used by snipers on both sides of the Civil War to great effect at relatively long range. You might consider that approach as it works pretty good and is not that hard. Modern patched bullets soak the paper in bullet lube.
Worth a try

KB

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sounds like maybe I should be sticking with the traditional molds, or maybe ones with slightly less lube grooves since it sounds like it's more for displaced lead or at least checking for actual fitment of bullets.

I've never had mnewcomb59's issue. But then, not one of my sizing dies is the size it was when I bought it. I modified them to exactly what the firearm wants. I use both grooved and solid, across multiple calibers. I should mention, though, that I've never had a goal of shooting farther than 100 yds with any of my cast. If you're shooting 500 yds, you'll find things to be problematic that I would never even notice.

The two rifle molds I use have one grease groove. I use the groove to grab the bullet with long tweezers and stand them up to cook. Doesn't remove the powder from bearing surface.

I PC all of my projectiles. I have not noticed a difference between bullets with lube grooves or not (except the price of molds). If you are going to be feeding through a lever action, a crimp groove might be nice.

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Originally Posted by Meatpuppet

I PC all of my projectiles. I have not noticed a difference between bullets with lube grooves or not (except the price of molds). If you are going to be feeding through a lever action, a crimp groove might be nice.

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Seems like the 45-70 molds have at least a crimp groove but I guess I'm leaning towards any molds. If I can find what I want with lube grooves, I'll get that, or without if I"m buying something new from someone like NOE/MP/Accurate.

I have recently had Accurate make me a 32-20 mold with the standard Lyman 311316 tip and straight walls for powder coating. I’ll shoot it in a S&W 1905 4”. Haven’t used it yet.

There are two issues that you should consider when choosing a boolit for powder coating. One has already been addressed: the displaced material from having the rifling impressed into the bullet needs a place to go. If you use a smooth sided plain based bullet the material can be pushed back to form a skirt at the base of the bullet. This has the potential to hurt the bullet's accuracy, as anything that deforms the base can do that. A possible remedy for this is to choose a gas checked design bullet. You can shoot this bullet either with or without a gas check, and the step for the gas check will give the displaced material a place to go so that it won't deform the bullet's base.

The second thing to consider is the bullets nose. Powder coating can increase a bullets diameter by up to .002" Sizing dies only size the driving bands, not the nose. If the bullet is a bore riding design, or has a nose profile that closely matches the firearms bore, doing a shake and bake powder coating might increase the bullets nose diameter making it difficult (or sometimes impossible) to chamber the cartridge. If you're going to have a custom mold made you should contact the manufacturer ahead of time and discuss any concerns about powder coating making the bullets nose diameter too large to fit the chamber. If choosing a factory mold design try to pick one that will minimize this problem. Using nose sizing dies can sometimes be problematic, so it is much more desirable to get a mold ahead of time that will cast the correct profile for use when powder coating.

If you have a lube groove, particularly a deeper one (not those very shallow lee ones), it acts as a crumple zone, causing a better case seal, and causing both front and rear bands to upset and thus obturate better.

I’m not expert, but I read a bit about lube/no lube rings on a cast bullet before I placed an order. We had several conversations along the way.

I have PC’d 9mm, 10mm, 38-55 with no issues and very little growth in bullet diameter. I have also seen no PC scrubbing off in the barrel whatsoever. As far as accuracy, I’ll be shooting a 1911 year 1905 4”. Mostly as a ranch pistol out to 15 yards.

https://www.ssusa.org/content/accura...-cast-bullets/

I powder coat all of my cast boolits and they all have lube grooves. I can regularly get sub - MOA groups with all of my scoped rifles at 100 yards. I also get very good accuracy with them in my pistols and revolvers.

I can confirm that my HiTek coated 147 gr 9mm bullets get more velocity from a given powder charge if they have a lube groove vs similar designs of same weight but slab sided. I also assume that’s related to reduced bearing surface.

All my coated bullets have lube grooves because that is what I had before I tarted coating. If I were buying new molds today, I Still would likely opt for grooves. No grooves makes it a unitasker, I am not a fan of unitasker tools if possible. Though maybe smooth bullets will work with alox, just never tried it.

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Originally Posted by kevin c

I can confirm that my HiTek coated 147 gr 9mm bullets get more velocity from a given powder charge if they have a lube groove vs similar designs of same weight but slab sided. I also assume that’s related to reduced bearing surface.

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I have the opp result with pistol bullets. With more bearing surface, higher pressures & higher vel. With sim bearing lengths & identical powder charges, the smooth bullets are faster.

I had Veral Smith cut one nlg 9mm mold a few years ago, but I've come to the conclusion that there is no advantage to omitting lube grooves and potentially a disadvantage like Fred alluded. My other molds have lube grooves.

I had Mihec make me a 358-146 HP NLG (no lube groove) mold to PC for my 1894C in 357 Mag. It is the most accurate bullet I have shot out of it and sub MOA groups are easily obtained from it. BTW - it is death and destruction on hogs!

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Originally Posted by fredj338

I have the opp result with pistol bullets. With more bearing surface, higher pressures & higher vel. With sim bearing lengths & identical powder charges, the smooth bullets are faster.

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Then maybe some other factor I don’t recognize accounts for my results.