Lee .300 BLK mold question (309-230)

[Moonie]

lee doesn't make 310 sizer, i wish they did.

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It's really easy to open up a .309 though.

[dimaprok]

It's really easy to open up a .309 though.

I've read that but when i tried with my 358 open up to 359 it didn't work. well maybe .0005 what kind of abrasive do you use?

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[Boolseye]

I’ve lapped a few molds successfully (and a couple not-so-much, you have to go slow and methodical)
Plain old NAPA valve grinding compound will do the trick, or you can get clover abrasive grease in 4,6 or 800 grit. I think the NAPA stuff is around 320 grit, but it does a good job. Then final polish with comet cleanser paste. Beagling is much easier if you can get away with it, also non-permanent.

[NoZombies]

I was lucky and ended up with 2 of the Lee molds that drop at .310 in WW alloy. I'm running them PC'd and sized .309 through a Ruger bolt action with a AAC 762SD and loaded at about 970 FPS with 1680. The loads are quiet enough to make grown men giggle when shooting the rifle.

[JayT]

You can always enlarge the mold a bit by "beagaling" or spinning a cast boolit with a bit of rubbing compound inside the closed mold. I did that on my .401 TL mold for my polygonal barreled Tanfoglio, and my 112 gr 309 lee M1 carbine mold. They now drop .0015 larger than original. If you go too far, get a .310 or .309 sizer (cheap Lee one is fine) to get it just the right size.

I’ve read up on the different methods of enlarging molds, but the rubbing compound is one I haven’t heard before. Sounds interesting. Just normal automotive rubbing compound? Attach the bullet to maybe a thin screw to make a bullet-sized “dowel”, essentially, and give it a few turns?

Furthermore, in the same reasoning, since I won’t be casting for supersonic rounds, is it necessary to keep the boat tail on the bullet mold? As I understand boattails, they are used to stabilize the bullet at high speed. As it is my intention to shoot only subsonic, can I “dowel” out the base of the mold with a sized dowel rod and minimally abrasive sandpaper to create a pb mold, or would you advise against that, since the boat tail should aid in bullet seating? I plan to use a Lee universal case mouth expander to bell the mouth slightly to prevent swaging of the bullet as I seat it.

Thanks for the responses, gentlemen.

[popper]

I have Lee sizers 308,09,10,11,12 from the factory. Beagle ( strip of tape on the mould edges, then size down - will eliminate most of the BT - but the nose might be too large. Don't have that mould but this has worked well for OPs.

[Grmps]

It's really easy to open up a .309 though.

I opened a 308 to 3095 and have been happy with the results.

Are you powdercoating?.

Yes I either powder coat or HiTek coat everything. I'm not a fan of lube

[mto7464]

I have two molds they drop small. Powder coating with smokes powder brings them up and I size to 309. They shot ok but not great. No feeding issue at all. I am going to enlarge them just a bit someday. Overall I like the design and glad they drop small or else I could not powder coat with out the nose getting too big. Wish the boattail was gone an had a slight meplat. Tried to get rid of it on one of mine and messed it up a little, tried to do it with a drill press but got a little off center. But they're cheap.

[Boolseye]

There are some good threads on lapping as well as beagling-I will suggest a search.
The key is to go really slow and cast new boolits regularly to check your progress. Very easy to wreck a mold. Don’t even bother trying to remove the boat tail, it would be a huge chore. I recommend not attempting a lap of this mold, actually. I think it would be a poor pay-off. Beagle it or move on, you’ll be glad you did. For the amount of work it would take to lap this thing out cleanly you could just buy a NOE. Partly the reason I say this is that some boolits seem to respond well to lapping (large pistol boolits, for instance) and others don’t. I suspect the big Lee falls into the latter camp. Not trying to discourage, by all means go for it if you like, you’ll certainly learn something regardless.

[JayT]

Ok, so here’s my plan. This will be my first casting, so please jump in if I’m missing a step.

First, I’m gonna drop some bullets from the mold and check for size. Then, powder coat and check for size again. Assuming no size issues, assemble projectile and cartridge into a dummy round and check magazine feed and chambering. Remove round and check for shaving on the bullet nose. Remove projectile from cartridge and check for any shaving due to seating. Assemble 5 live rounds, running all the checks that I would with any hand load. Then a 10 foot suppressor-less paper punch to verify stability and check velocity before screwing the suppressor on and repeating paper test. Once it’s verified that the round is stable, subsonic, cycles the action, feeds the next round, and holds open on an empty magazine, it’s time to dial in the powder charge and seating depth for best function and maintaining subsonic velocity.

Anything that I missed?

[Boolit_Head]

10 foot may not be far enough to tell about stability.

[Boolseye]

Looks good to me. That boolit is a very reliable feeder in the 300 BLK.

[JayT]

10 foot may not be far enough to tell about stability.

I just really want to ensure that the bullet is coming out of the muzzle straight. My biggest concern would be a baffle strike or end cap strike on the suppressor. As long as it’s a good clean hole through paper at 10’, it would have been straight coming out of the muzzle.

[MT Chambers]

There are so many .30 cal. molds out there that have been proven accurate in BR competition, between 160 and 220 grs.., molds like 311284, 311299. Saeco 315, noe copies of Eagan molds, etc. My experience with a .300 whisper was poor accuracy at subsonic and the same bullet showed increasing accuracy as the load got heavier. Seems as you have talked yourself into a cheap mold, however I hope you enjoy.

[JayT]

There are so many .30 cal. molds out there that have been proven accurate in BR competition, between 160 and 220 grs.., molds like 311284, 311299. Saeco 315, noe copies of Eagan molds, etc. My experience with a .300 whisper was poor accuracy at subsonic and the same bullet showed increasing accuracy as the load got heavier. Seems as you have talked yourself into a cheap mold, however I hope you enjoy.

This is my first attempt at casting. I’m looking to see if I can produce a bullet first. If I can, and I decide that I like it enough to keep doing it, I’ll step up to an NOE 311-247.

[Handloader109]

Couple of comments from someone new to 300bo casting, make up a few w/o primers and powder and get your oal and crimp correct to function. Then add powder and primer and go shooting a handful. The noe mold gave me fits after powder coating as even after sizing to .309 after pc the loads would hang up. Had to really crimp well. But once I got length and crimp down they shoot great in my 9inch thru suppressor. Get some cfe blackout powder...

[jimb16]

I had some feed problems early on with my BO. Traced the problem to inadequate crimp. When using cast make sure you eliminate ALL of the expansion of the case mouth. You don't need much crimp, but you do need to completely get rid of the case mouth belling. Once I found and eliminated that problem, I've had perfect feeding ever since.

[gary0529]

J--
Glad to see you say you were just punching paper with those--I have been shooting 300 Whisper long before the Blackout was coined-strictly for suppressed use out of a custom made bolt gun with can.
Nothing I cast, and I will stand by that comment, will open at those speeds. Regrettably I have had to track and finish a couple of deer that were penciled through with heavy slow lead rounds. Quiet-yes. Accurate- sure. The hours I spent tracking wounded deer and the thought that I did NOT get a fast humane kill were troubling to the point that I only use either Lehigh or Outlaw States rapidly expanding or fragmenting bullets for game.

They work!!!

Gary