Removing mold lube grooves?

[ChrisCbr]

I powder coat so have no need of the lube grooves in my Lyman 40 mold. Has anyone attempted to remove the grooves section before and have a technique to do so?

[mozeppa]

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[longbow]

I am a little unclear on why you would want to remove the lube grooves. Are they causing some sort of problem?

Also, if you ever wanted to sell the mould or use it as a GG boolit again you would lose that option.

I am not even exactly clear on what the benefit of using smooth boolits for powder coating is. Does it give that much more bearing surface that you can increase velocity or what? Just looking for an education here as my impression so far is that the lube grooves don't hurt anything when powder coating.

If you are bent on altering the mould, I would not attempt it yourself unless you have a decent machine shop and skills.

Best to send the mould to someone like Erik at Hollowpoint Moults:

http://www.hollowpointmold.com/

I have not had Erik do any work but have heard only very positive comments about his services.

Longbow

[ChrisCbr]

i ordered whats called "slick sided " molds for powder coating from hardlines industries.

https://www.hardlineindustries.com/

Those hardline molds look good. How's the pricing compared to accurate molds? Any idea if they ship out of the states?

[ChrisCbr]

Longbow, yes I have the equipment though the best I can think of technique wise is to use a t-slot cutter or similar of exact diameter in my CNC mill.

The lube groove reduces the bearing surface and makes what would otherwise be a 180 gr boolit 175gr. The lube grove influences how I can seat/crimp the boolit and I suspect would adversely affect the seal in the bore given that it forms a void.

[mozeppa]

Those hardline molds look good. How's the pricing compared to accurate molds? Any idea if they ship out of the states?

$140 each ...4 cavities! sprue plate is heavier than any other i've seen....VERY WELL MADE! (no ...i don't own any stock in this company.):bigsmyl2:

[bigarm]

I have 3 moulds from Hardline and can attest that they are very nice. 2 of them are 2 cavity and one is 4 cavity and all poured great bullets almost from the first pour. No, I don't own stock either, just a satisfied customer.

[gunoil]

I own hardline molds too, incredible! Worth the money, get and cast the real deal. RCBS pro-melt too. Then correct ingots, your done and can move attention to other problems in your shop.

Wish i had know to buy quality casting equipment in the beginning.

[longbow]

If you have a CNC mill and can locate the center of the cavities within a thou you should be able to orbit the cutter and remove most if not all the lube groove(s). Getting to a thou or better and dead in line with the axis of the cavity is likely the biggest issue. If you mill off center then you will have an out of balance boolit.

Personally I think the lube grooves are a benefit to sealing. I have shot smooth lead boolits in both my .44 Marlin and my .303's and find that gas cutting tends to end at a lube groove but continue on a smooth boolit.

Each lube groove not only gives displaced lead a place to go but also it is a bit of an expansion chamber for gas that leaks by and in my experience there is always some leakage (just look at slow mo video of guns being shot and there is smoke leaving the muzzle before the bullet).

Not sure how the PC reacts to any leakage/gas cutting so maybe a bit different but I still can't see a real disadvantage to the lube grooves. I suppose if you want to play around with seating depth then the crimping issue may be a problem with lube grooves though.

Has anyone using PC noticed a significant difference between performance and accuracy between smooth boolits and those with lube grooves?

Has anyone recovered boolits and checked for gas cutting?

Like I said, I am looking for some education here. I may give powder coating a go in the future.

Longbow

[Boogieman]

I removed the grooves from an old Lee 45 cal. SWC .H&G#68 style. Boolits recovered from snow at 50 yds. didn't show any gas cuttinng. accuary was the same as grooved boolits I have some pictures posted back on 3/04/14

[bangerjim]

WHY??????????????

I have many dozens of standard and microgroove lube groove molds that PC perfectly!

I have 2 NLG molds that I can see absolutely ZERO benefit in.

The standard AND microgroove boolits coat and shoot perfectly.

Unless you have a precision milling machine, a REAL milling vise, boring head, boring bars, and other machinist's tools, you will only ruin a good mold trying to drill the grooves out. A drillpress is not a good idea...for precision. And we are talking thousandths of an inch in molds......RiGHT????????

Some on here have done it with a drillpress and a drill........but I require much more accuracy and precision in my castings!

bangerjim

[Boogieman]

Bangerjim is right about the proper tooling to do the job. I did mine with a drill hand turned it does not cast round boolits but once sized & powder coated they will group under 2" at 50ft 2 handed standing out of a 1991A1 Colt. Thiis was a loose old Lee 200gr.SWC[H&G#68 style]. I would not try this on a good mold. If you try this clamp the mold in a machinist vice do not bolt it to the drillpress table put the drill in the chuck and turn it BY HAND. A chucking reamer works better if you have one. Like Banger I found grooved PC'ed work just fine. Ijust wanted to try some slicks Don

[DR Owl Creek]

Don't ruin a good mould! Sell it and buy whatever it is you think you want instead.

Dave

[ChrisCbr]

Have decided to relieve a carbide end mill to accommodate the mold base taper and then dial it in on the CNC machine. Have also ordered a hardlines industries smooth walled 6 cavity mold in 190gr. Can't wait!

[leadman]

NOE also has some molds for smooth sided pistol boolits.
I have been thinking of smooth sided boolits in a rifle. I think it may aid in the ability of the boolits to group accurately at jacketed velocities.

[bangerjim]

Have decided to relieve a carbide end mill to accommodate the mold base taper and then dial it in on the CNC machine. Have also ordered a hardlines industries smooth walled 6 cavity mold in 190gr. Can't wait!

If you have the machinist skills to grind down a carbide end mill and then mill out the cavity on a CNC mill, then YES you CAN do it. You did not say you had those tools or skills at your disposal. Most on here asking that question try doing it with a cheap wobbly-quill bench top HF drill press, a HF garbage drill press vice and either a standard twist drill or a chucking reamer!

Have at it!

banger

[longbow]

Another option for making smooth boolits is the Ideal Cylindrical moulds:

126141
I make a similar mould but use 1 1/2" round bar so a bit more skookum and a more traditional sprue plate.

I have made them in several calibers and for shotgun slugs. All work well and are easy to make with just a lathe.

I have been planning to make a multi-cavity version out of square or rectangular stock but haven't got to it yet. With a CNC mill you should be able to make one easily.

Longbow

[popper]

Why bother on a 40 - you only gain ~ 10 gr, 1%? I have a shallow groove 9mm mould that does fine. I use slick sided for rifle, but I push them hard. The BB makes loading a lot easier & has NO effect on accuracy, may improve it a tad. Personally, I'd buy a custom to exactly what you want, shoot and compare the two, then sell the one you don't like.