pc and tight chambers, gauge suggestions?

[ryokox3]

Hi all,

Some of my pistols have tight chambers that are not forgiving of a standard boolit mold with pc, especially with a shake and bake method. So I decided to look into some chamber checkers to help me see if the boolit will work. My problem is that some are for just the resized brass. Which ones will check the boolit portion so if a thick coating would cause problems the gauge would indicate it? If it matters I'm looking at .380 acp and 9mm luger.

Thanks,
Ry

[TexasGrunt]

L.E. Wilson.

http://www.lewilson.com/pistolmaxgage.html

[BUCKEYE BANDIT]

^^^^^^^^^ Wilson for sure.

[pergoman]

I have dealt with that same issue RYOCOX3, especially with the 9mm's. I size mine to .357 for all of my 9's, autos and revolvers. None of my rounds will drop into a Wilson or Dillon gauge but they all pass the "plunk" test in the barrel. I got a 6 caliber gauge block as a gift from one of the bullseye leagues I shoot in and that also works. It is obviously cut a little larger than SAAMI spec but better approximates my chambers.

[DougGuy]

You already have the best gauge you could ask for, your own barrels. Pull the barrel and use it for a go/no-go gauge. You will want ammo to drop in and spin freely.

Generally speaking, most interference comes with the PC boolit not wanting to enter the throat or freebore in front of the chamber. The proper way to relieve this is by throating the barrel which will get you a generous amount of .3585" freebore in front of the chamber and a 1.5 degree leade in to the rifling. This is very easy on PC and shoots them very accurately with zero feed issues.

Interference in the chamber itself is one that you usually cannot detect until after the barrel is throated since a boolit large enough to cause the shoulder of the case not to seat fully in the chamber often will not go into the throat either.

You can try seating one of your boolits upside down in a dummy round so that there is only the end of the case mouth and no boolit to interfere with the throat, see if this dummy will plunk and spin freely. If it does then you only need to be concerned with the throat itself.. If it doesn't then you can address the problem by sizing smaller and trying the dummy again until it fits in the chamber easily.

[runfiverun]

the chamber is your best gauge.
it is the only gauge your ammo has to actually fit.

like Doug points out above.
sometimes a tight chamber is not really a tight chamber at all but a non existent throat that makes the front of the chamber seem like it is.
your boolit just ain't got no where to go except to jam into the rifling.

[rsrocket1]

I was doing this also but sizing my boolits with a 0.358" 38 special sizer for 9mm. Recently I tried sizing them to 0.356" with the 9mm Lee push through sizer and find that they shoot just as well in my 92fs (0.357" groove) as they do in my M&P 9 FS and Shiled (0.3555" groove). Both have lands that are narrow enough to engage a 0.356" diameter bullet and I still get NO LEADING!. Just carbon fouling that mops up with a single patch and CLP or just about anything else followed by a dry patch.

I already had the S&W's but when I got the Beretta, I was worried that I would have to make multiple sized bullets for the different bores. The PC really does act like plating and prevents gas cutting of the lead bullet long enough for the bullet to exit the muzzle and not cut through the PC layer. Either that or the base is being bumped up enough to seal off the gas. In either case, I'm happy.

[bwframe]

The question is whether to throat barrels or load with shorter OAL's ?

[DougGuy]

The question is whether to throat barrels or load with shorter OAL's ?

Assemble loads as recommended by published load data from powder manufacturer's data or from reloading manual data. If they don't "plunk" then the barrel may need throating since published load data is within SAAMI specs for the caliber.

If you want to size .001" or .002" over the groove diameter and there isn't any freebore or there isn't enough freebore or the freebore is smaller in diameter than the boolit, throat the barrel.

It is pretty much an industry wide trend to throat only for jacketed factory produced ammo, which is almost always too tight for cast boolits. Barrel throats and cylinder throats need to be .0005" to .001" over boolit diameter for cast boolits.

Seating deeper in the case is a poor workaround for a properly done throat. It works, people do it, but you have to compromise load data to not generate an over pressure event when you seat deeper, most times feeding in an autoloader is better with a longer COA, but the longer smoothly tapering throat shoots very accurately, you experience either zero or very little leading, pressure is lower than with the tighter more abrupt leade in to the rifling, and you can seat out as long as it will fit in the magazine.

Throating is an inexpensive one-time investment that cures a lot of problems shooting cast boolits, and if you want to PC it's almost mandatory to make the throat sufficient enough in length and diameter that the PC'd boolit will fit without interference.

[bwframe]

Assemble loads as recommended by published load data from powder manufacturer's data or from reloading manual data. If they don't "plunk" then the barrel may need throating since published load data is within SAAMI specs for the caliber.

If you want to size .001" or .002" over the groove diameter and there isn't any freebore or there isn't enough freebore or the freebore is smaller in diameter than the boolit, throat the barrel.

It is pretty much an industry wide trend to throat only for jacketed factory produced ammo, which is almost always too tight for cast boolits. Barrel throats and cylinder throats need to be .0005" to .001" over boolit diameter for cast boolits.

Seating deeper in the case is a poor workaround for a properly done throat. It works, people do it, but you have to compromise load data to not generate an over pressure event when you seat deeper, most times feeding in an autoloader is better with a longer COA, but the longer smoothly tapering throat shoots very accurately, you experience either zero or very little leading, pressure is lower than with the tighter more abrupt leade in to the rifling, and you can seat out as long as it will fit in the magazine.

Throating is an inexpensive one-time investment that cures a lot of problems shooting cast boolits, and if you want to PC it's almost mandatory to make the throat sufficient enough in length and diameter that the PC'd boolit will fit without interference.

Thank you for the info.

I'm running into this throating issue in a few barrels. Are folks reading this familiar with buying the tools to do this yourself? The pitfalls of possibly screwing it up?

[DougGuy]

Thank you for the info.

I'm running into this throating issue in a few barrels. Are folks reading this familiar with buying the tools to do this yourself? The pitfalls of possibly screwing it up?

Most send the barrels and cylinders to me for throating, you may send a PM and describe which calibers, barrels, boolits, etc..

BTW.. Welcome fo the forum. You will find a lot of information here for just about anything related to making and handloading cast boolits, this is probably the best problem solving site on the net for firearms related issues.

[OS OK]

If there is a chamber throating issue there is a chance that using a 'clear gloss PC' will squeak you by that. The clear gloss doesn't have to carry color pigment and it covers fantastically even and 'thin'. I love colors as much as the next guy but I find myself using the clear gloss more and more in the Colt 1911. I size to bore, shoot a soft blend @ 10 - 11BHN Pb @ 850 - 900 FPS with the 200g. Lee SWC's (both styles, lube groove and tumble lube) also the Lee 200g. RNF's.
My colt has shallow lands, the casts don't strip or skid and I have '0' leading issues.

Just a thought you might consider.

[bwframe]

Most send the barrels and cylinders to me for throating, you may send a PM and describe which calibers, barrels, boolits, etc..

BTW.. Welcome fo the forum. You will find a lot of information here for just about anything related to making and handloading cast boolits, this is probably the best problem solving site on the net for firearms related issues.

Thanks Doug! I've been lurking for a while. Just got busy casting/coating this past year.

I'm pursuing optimum 9mm loading for USPSA and Steel Challenge matches. I shoot production pistols and the new PCC division. For pistols we prefer to load heavy bullets long for reliability and soft shooting. PCC is still somewhat of a mystery for optimum loading, folks are all over the place.

I'd really like to do this throating myself if this is something that a "shade tree" gunsmith like myself could accomplish without too much room for error. Some of the folks over on the Enos forum have been doing this themselves. Some of the most popular PCC barrels are short throated, for factory loaded ammo. I have a couple of these PCC barrels, on top of 3 pistols that might be used.

Once these barrels are throated the way I'd like for longer loading of cast/PC'd boolits, are they compromised in accuracy for factory loads? Specifically, heavy self defense hollowpoints?

[DougGuy]

Thanks Doug! I've been lurking for a while. Just got busy casting/coating this past year.

I'm pursuing optimum 9mm loading for USPSA and Steel Challenge matches. I shoot production pistols and the new PCC division. For pistols we prefer to load heavy bullets long for reliability and soft shooting. PCC is still somewhat of a mystery for optimum loading, folks are all over the place.

I'd really like to do this throating myself if this is something that a "shade tree" gunsmith like myself could accomplish without too much room for error. Some of the folks over on the Enos forum have been doing this themselves. Some of the most popular PCC barrels are short throated, for factory loaded ammo. I have a couple of these PCC barrels, on top of 3 pistols that might be used.

Once these barrels are throated the way I'd like for longer loading of cast/PC'd boolits, are they compromised in accuracy for factory loads? Specifically, heavy self defense hollowpoints?

Nope to answer your last question, they just work.

As far as doing it yourself, the reamer and pilots cost more than double what I get for a throat, crown & polish job on a stainless or carbon steel barrel, and if the barrels are salt bath hardened the cost of the reamer goes up 4x because carbide is the only thing that will throat a Glock, poly framed Springfield, CZ, S&W M&P, so you are in a whole different briar patch now, and the carbide reamers are lucky to get 10-12 barrels throated before they need reworking.

FWIW, the same 9mm that holds the world record year after year has .100"+ of freebore, and a 1 degree leade in so it is throated out nice and long exactly like I do them. This from Jerry Keefer. They just work what can I say..

[Phantom30]

2 cents IMHO. Given that there is no problem firing jacketed bullets, then the problem is the mold not the chamber or the process. Molds traditionally cast full spec boolits. PC should be treated like a jacket, so you buy a mold that casts a boolit core under full spec. PC and sizing brings it back to spec like a factory load.

[DougGuy]

PC should be treated like a jacket, so you buy a mold that casts a boolit core under full spec.

Not quite.. You buy whatever mold you like, then run boolits through a sizing die to "undersize" them prior to PC which then brings the size up to the final desired diameter. Run them through a final sizing die after PC to get rid of any high spots.

[bwframe]

More good info. Thanks again folks!

[reddog81]

2 cents IMHO. Given that there is no problem firing jacketed bullets, then the problem is the mold not the chamber or the process. Molds traditionally cast full spec boolits. PC should be treated like a jacket, so you buy a mold that casts a boolit core under full spec. PC and sizing brings it back to spec like a factory load.

That might work out OK, if someone made such molds. I am aware of people making no lube groove molds for PC, but I've never heard of anyone making undersized molds.

[popper]

Custom mould with a smaller nose or Hi-Temp paint in the nose area. Most common problem is one size doesn't fit all. No chamber checker is designed to check fit, even the Sheridan. Use your barrel.