Help diagnose a problem

[chris in va]

Shot my first cast boolits today, 9mm 124gr TC tumble lube with 3.5gr (EDIT: 4.0gr) of 231. They all chambered/fired/ejected fine, but accuracy was all over the map out of both my HiPoint carbine and CZ 75BD. I can usually hit a 4x8 steel plate at 100 yards with the carbine and FMJ, but not with these. Same issue with the CZ at 25 yards on a swinger.

I've read about slugging the barrel, but have no idea how to do that with the carbine as there's no way to push anything through from the chamber end like on a rifle. Frankly I have no idea how to do it anyway. The tumble lube boolits claim no sizing is necessary, so I'm confused.

Leading was minimal after about 250 rounds in the carbine. I bought some copper scour pads as recommended and it removed what there was. Nothing really in the CZ.

Is the lead too hard? I've been water dropping them.

[chemist308]

I'm a newb, but can you field strip your carbine? Then you should be able to slug it then. When I did my 9mm, I put the barrel in garage vise and I pushed a cast 38 lead bullet through it using a mallet to seat it into the muzzle, then a cleaning rod I wasn't partial to, with the mallet to get it the rest of the way through--note: do this with a lead bullet not a water dropped wheel weight.

When you load, are you watching your overall case length? I reloaded 9mm for the first time and found I really had to watch this one. Seat the rounds inconsistently and you would have to be messing with the pressures. Just a thought.

[wallenba]

To slug the carbine melt some cerrosafe, plug the barrel with some clean dry cleaning patches and fill the chamber. Allow 1 hour to cool, then measure. It will continue to shrink as it cools. 1 hour is important. http://www.midwayusa.com/browse/BrowseProducts.aspx?tabId=1&categoryId=8662&categoryString=9315***685*** The accuracy issue could stem from a lot of things, even a combination of things. Boolit dia., boolit weight variance, case length variation affects the crimp, powder charge, or the gun. Tough one to work out. Work out a plan and narrow the suspects down.

[Nora]

You could also use a soft lead boolit or buck shot to do the slugging. Make sure the bore is clean and has a fresh coat of oil in it. There's also no harm in doing it from the muzzle end. In the case of the Marlin's, it's the only way to do it with the side eject and all. Start it with a plastic or brass mallet then use a hard wood dowel rod cut into about 6" sections. As each reach the muzzle, add another one till the slug drops out the chamber. Then measure. Just make sure not to use anything for a hammer that is harder than the barrel to slug it with, as to not beat the crown any. Hope that helps some.

Nora

[454PB]

You can slug the barrel starting from the muzzle, just be careful and keep the rod away from the rifling. I use a piece of brass brazing rod that's 1/4" diameter. I put a tapered point on the "boolit" end to keep it centered on the slug.

The first time you do this, it helps to have an assistant, but after some practice, it can be done alone.

A dead soft piece of pure lead works best, and lubicate the barrel and slug before hand.

[randyrat]

3.3 grains of W231 is starting for that bullet. Did you try a starting load and work your way up to 4 grains? As you get closer to 4 grains you may have to harden your bullet a bit, depending on your gun. (just water drop WWS)
The tumble lube bullet advertising always says no need to size, but i do anyway to keep them consistant. Also to keep an eye on my casting technique/consistancy.
Some powders won't work in YOUR gun till you get close to max.

The reason you may need to harden your bullet up a bit is; 4 grains of 231 under 124 gr lead bullet is over 30,000 PSI

[Wayne Smith]

Randy, he is water dropping. Slug your barrel. You don't know the basic info necessary until you do. Your hardware store has brass rods - at least mine does. You can use steel if you wrap a nice layer of duct tape around it at a couple of points to keep it off the bore. Yes, you do it from the muzzle - do a pound slug to get a real look at your throat. I use a round ball cast of pure lead, tap it into the bore with a ball pein hammer until there is just a ring of lead left over the muzzle. Then place the brass rod in the middle and tap away. If you don't have round balls you can get a hollow core sinker - probably at your hardware store?

After you've done this you have to measure it - are you equipped to do so?

[randyrat]

Your right Wayne. You have to know the basic stuff like grove diameter first then size your bullets accordingly. Then work the load up starting with ACWWs and as you get closer to max harden the bullets up a bit, only if you need to.

[chris in va]

I'll try the sinker slug idea, and it'll have to be done from the muzzle as it is a side eject. If 3.5gr of 231 is considered a light load, perhaps it's not 'obturating' correctly with the bullet being around 18 hardness?

[lwknight]

I'll try the sinker slug idea, and it'll have to be done from the muzzle as it is a side eject. If 3.5gr of 231 is considered a light load, perhaps it's not 'obturating' correctly with the bullet being around 18 hardness?

I affirm that 3.5 grains of 231 is entirely too light for a hard cast 124 grain boolit to obturate. I'm surprised that it even operated your gun reliably. Well.. the highpoint is a blowback action. I've never had a blowback other than a 22.

[chris in va]

Here's something else to throw in the mix. Keyholing.

http://img200.imageshack.us/img200/5531/imgp4870.jpg (http://img200.imageshack.us/i/imgp4870.jpg/)

And I discovered tonight they were charged with 4.0gr of 231, not 3.5 like I thought. The manual shows more of a charge for a carbine, so wonder if that's the issue.

[VintageRifle]

Some good instructions for slugging your barrels. Requires sections of wooden dowel rods.

http://www.surplusrifle.com/reloading/slug/index.asp

[lwknight]

You really need to slug the barrel.
You already said that the barrel was clean but did you check around the chamber head?
The 124 grain boolits do not require much twist like heavier bollits would.
9mm is not really a 100 yd type cartrige IMHO.

[Wayne Smith]

Keyholeing is almost always a boolit too small. Again, slug the barrel, we are all guessing until we know some facts.

[454PB]

I suggest you stay away from hardwood dowels. Sooner or later they begin to shatter and mash over on the ends......then you've got an expanding bore obstruction on your hands.

[MtGun44]

What Wayne said. Too small for the bore. Use a steel rod with some tape rings or
a brass rod. 454PB is dead on, too.

9mm seems to be almost always too small, esp if you buy commercial cast. I'm sending
some .357 diam 9mm Lee TC 120s to my brother since his 9mms are throwing them
sideways, too.

Bill