Reduced capacity cartridges using zinc

[GARD72977]

I have been thinking about using zinc to melt into the bottom of a 30-06 case and then drill the flash hole through the zinc. Im looking for 32 pistol type performance with very reduced capacity.

I know that the cartridge will no longer expand to the chamber but the neck should still expand to seal. The idea is to use pistol powder in the 06 to send a 130-150gr bullet in the 700fps range

Not sure how the zinc would hold up to the powder charge. It may need a oversized flash hole drilled and a brass insert pressed in to protect the mouth of the flash hole. I have a lathe and mill.

any thoughts

[rollmyown]

I think your idea has lots of promise. Where it might shine more is with the 577 450 case reducing to a 70 - 85 grain BP capacity reducing or eliminating the need for fillers.

[1johnlb]

You might greatly reduce the temp of the primer causing more misfires, pending on how deep you fill the case. Sorry, not to be to negative but you could also run into a situation where the zinc shifted forward increasing pressure or possibly creating a blockage.
If it was me considering it, and it's not, I would be more inclined to machining cases out of solid stock with a 30 cal cavity to fit the projectile. It still would have to overcome the distance and lost of heat from the primer to powder, not to mention expenses.

[reed1911]

I believe I would grab one of the .32 ACP adapters for your .30-06 and use that rather than follow this idea too far. There are a whole host of issues that I see you having problems from, that said, if you are careful and don't mind the loss of time, it may be an interesting project to do.

[garandsrus]

I don't know if it will matter at the pressures you are trying to get to, but by pouring molten zinc in a case, you are probably annealing the entire case, which is not normally a good thing.

[Artful]

I have been thinking about using zinc to melt into the bottom of a 30-06 case and then drill the flash hole through the zinc. Im looking for 32 pistol type performance with very reduced capacity.

I know that the cartridge will no longer expand to the chamber but the neck should still expand to seal. The idea is to use pistol powder in the 06 to send a 130-150gr bullet in the 700fps range

Not sure how the zinc would hold up to the powder charge. It may need a oversized flash hole drilled and a brass insert pressed in to protect the mouth of the flash hole. I have a lathe and mill.

any thoughts

I you have the lathe then I would take solid stock and make the case as you wish - be aware you'll want to neck size only or if possible cut it so that you can just thumb seat the boolit.

I have several brass reduced capacity cases that were made for 308 subsonic loading, and they work great in that they give full capacity loads of trail boss. Previously I had tried to make some by putting plastic/epoxy of various formulations and they all broke up sending parts down the barrel. Make sure you take depriming into account on your finished case.

That said you wouldn't be out much if you tried a couple of zinc experimental cases - just make sure to clean the inside well and I'd rough it up a little so the zinc can grab on the case walls.

[BAGTIC]

It would not necessarily increase distance from primer to powder. Make the hole big enough that some of the powder charge will fill the hole right down to primer pocket. With case with shoulder or significant taper either would keep insert from shifting forward or being expelled.

[SSGOldfart]

Humm [smilie=s:it's a good ideal just not to sure I'd be the one to try it I'm down to 1.1grn of bullseye pushing a Lee .311 92gr,boolet in my 308win sounds kinda like a pellet gun but it stops the cats from getting to my rabbits without waking the wife
Art how is your soild inserts expanding to seal the bore??
If anybody comes up with a insert that works for the 06 I'm in the market for two of them?? just keep the price fair:bigsmyl2:[smilie=l:

[country gent]

I would also consider a solid insert in the case turn a brass or bronze bushing to fit with a very light press fit and a .310 hole to fit from case head to just under shoulder. To install you will need to anneal necks and epand to straight walled case, press insert into place with a light coat of red locktite. allow to cure. then reform neck and shoulder. Remeber that the inside of the case is tapered and that will need to be maintained on the bushing/ sleeve as it will be to strong to size down in a reloading press. You could also make lathe turned cases to do this again the tapers will need to be correct as sizing isnt going to happen. Pouring ZInc lead or other material and drilling for flash hole will require a very long small dia decapping pin to de prime. Zincs melting point is also high enough to soften case heads.

[GunStuff]

Interesting discussion. Depriming - A large enough hole could be drilled through the zinc to accommodate a universal depriming tool. Case head annealing - Instead of using pure zinc to partially fill the case make up an alloy that has a lower melting temperature.

Experiment an post your results.

[nekshot]

I you have the lathe then I would take solid stock and make the case as you wish - be aware you'll want to neck size only or if possible cut it so that you can just thumb seat the boolit.

I have several brass reduced capacity cases that were made for 308 subsonic loading, and they work great in that they give full capacity loads of trail boss. Previously I had tried to make some by putting plastic/epoxy of various formulations and they all broke up sending parts down the barrel. Make sure you take depriming into account on your finished case.

That said you wouldn't be out much if you tried a couple of zinc experimental cases - just make sure to clean the inside well and I'd rough it up a little so the zinc can grab on the case walls.

I tried the epoxy, JB Weld route also and in the process I locked a win 94 action up so tight I had to pound in barrel and pound lever at same time. All I had was a little drill bit hole thru case up to neck but what ever powder I put in was way too much and I didn't dribble much in!!!!

[GARD72977]

Lots of good advice here. I thought about annealing the whole case but decided that filling a case with zinc and only using pistol pressures would not be a concern. Depriming is something I forgot about. Not sure that the length of the priming tube is a problem since there has been a lot of success making extended primer tubes the come to almost the base of the bullet.,

Thank guys

[country gent]

Alot of those primer tubes were made screw in so they could be removed for depriming the cases. A .060 pin 1 1/2" long is going to be pretty flexable and more prone to breakage than the short one normally used. You can get volumne after conversion with water capacity. Set case with fired primer seated on scales and zero scales fill to case mouth with water and make note of it. Look for other cases with same water capacity or close to it. This gives a rough idea of where to start.

[Pinsnscrews]

If you filled the case to the shoulder with the melted zinc, then, used an endmill to bore down the length of the hardened zinc in .309/.310 to the base, that would essentially give you a "30 Carbine ought six". I am not certain the zinc would live up to the temps of the burning powder, but at worse, instead of leading you might get a little zinc slag in your barrel....

how about taking the idea of Art's and making some out of solid brass, bore the center using an endmill, and just make the neck the same thickness as an actual 06... Bore the center .310-312 so you have the internal dimensions of a straight walled 30 Carbine only it would be 06 length...mill your primer pocket, and drill your flash hole, along with cutting the rebate and rim should not be a problem on the lathe.

[ohland]

Well... How about making a lost wax case casting. Take a case, fill with a casting compound, cut it open closer to the head so you get towards the widest part of the internal cavity, extract the casting, make some molds for brass inserts. Cut insert to fit flush to base of neck. Drill powder chamber.

Now the easy part. For a .308, anneal the neck and shoulder. Now open the mouth so it is a straight case. Think of the 358 Winchester... Insert prepared insert. Size mouth back down to .308, end up with FL die (or whatever)

Heck, the English loaded cordite in straight hulls, then sized the neck down...

Simple...

[country gent]

Its sounds a lot simpler thanits going to be. Opening up a 06 case to straight walled is going to be much closer to 45 cal than 35. Meaning 2-3 steps opening it up then inserting the insert into place hoping it will fit corectly and bottom out evenly. Then sizing back down to 30 cal from roughly 45 cal in 2 or 3 steps. You may end up annealing after the size up and then again after sizing down. If you could get rem, winchester, starline, or one of the case manufacturers to send you 100 30-06 cases before shoulder neck forming is done half the case work would be done for you. Brass attrition from this much working would be high.

[ohland]

Simple is not always easy... The most difficult part of all the methods is to fill the powder cavity, NOT have the filler break or move, and have the reduced volume open to the flash hole and the neck of the case.

It does not seem possible to cast a new case with diminished capacity. OK... how about making a mold with a brass tube as the center axis, then pour a suitable metal around the tube into the shape of the cartridge? Problem would be the strength of the rim since it isn't tempered brass.