Tuning up a revolver for lead.


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smovlov
August 13, 2013, 07:59 PM
I just got done shooting my second batch of reloads. I' shooting commercial cast 158gr lead SWCs over Titegroup in .38 and .357. I'm getting leading in the rear of the barrel in front of the forcing cone. I read this thread:

Leading problem with Taurus Tracker .38/357 loads.
http://www.thehighroad.org/showthread.php?t=724521

And I also read the Fryxell chapter on the topic. I also get lead in the cylinder throats. The bullets are sized to .356 to .357. From what I can read my barrel slugs out to be .355. The bullets are tight in the cylinder throats.

My questions are:

Should do like Fryxell says and fire lap the revolver? or

Should I just get the throats reamed? (if so... what size?)

Would cutting them at .358 allow too much gas bypass in the throat?

I think I get more Lead in it with the lower pressure .38 cases. Should I just move up to +P to get the pressure up on the bullets in the .38? I would like to work with what I have for now. I have about 400 .38 cases and only 25 .357 cases.

I do have a strong interest in casting my own and have been researching a lot lately. The revolver will see some jacked rounds but not many. The leading is not too hard to get out of the barrel but it is difficult to remove from the cylinder throats. I mainly just don't want to scrub so much.

On another note. I did the best shooting Ive ever done today while testing. a nine shot group of 2" and a five shot of 1.4" both rested and at 7 yards. No Bullseye shooter but I'm happy. Maybe one day Ill get it out to 50yd. :cool:

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GLOOB
August 13, 2013, 08:51 PM
At 7 yards, you're just seeing how good a shot YOU are. You're pretty good. If you want to see how accurate your load is, you need to shoot at 50 yards, at least. I test my pistol loads at 100 yards, cuz if a bullet is wobbling, it'll be night and day, at that distance.

If your bullets are shooting straight and accurate, I wouldn't mess with the cylinder throats. You might want to ream them a little, but just so they're all the same size.

A lot of revolvers have a stricture in the bore near where it's screwed into the frame. This can reduce accuracy with cast bullets. But the last word in accuracy comes from the muzzle. If the bore is as tight or tighter in the muzzle as it is anywhere else in the gun (including the cylinder throats), then chances are good that it'll be a shooter. If your gun has a stricture, and it's tighter there than at the muzzle, then you may be losing some potential accuracy with cast bullets.

If you think you have a stricture, put a cleaning rod down the barrel with a tight patch. You would be able to feel things tighten up near the forcing cone.

Personally, I haven't done any fire lapping, but the theory is sound. As the bullet travels down the barrel, the lapping compound gets smushed into the lead. So the chamber end of the bore should get polished out more than the muzzle end. This is good. The only downside is that the throat or cylinder end might get polished too much. AFAIK, this is more of a concern with a rifle, though. The throat erodes over time and eventually wears out the barrel. On a revolver, this shouldn't really be a big deal. If I had significant accuracy issues due to a stricture, I'd probably try firelapping. But as long as the gun shoots good, I'd leave it alone. If fouling is the only issue, I'd try different loads, bullet hardness, and lubes.

rcmodel
August 13, 2013, 09:06 PM
From what I can read my barrel slugs out to be .355.That would be highly unusual with a .38/.357 revolver barrel.
It should slug .357" or very close too it.

Slug it yourself and measure it.

The bullets are sized to .356 to .357.That would be highly unusual too, considering lead bullets for a .38/.357 should be at least .358".

rc

SlamFire1
August 13, 2013, 09:22 PM
Titegroup burns clean because it burns hot. You can try two things: cut your loads and see if that reduces the leading or try 3.5 grains Bullseye with a 158 cast bullet in the 38 Special. Never had any issues with leading and cast bullets with that load.

Walkalong
August 13, 2013, 09:31 PM
I also get lead in the cylinder throats. Your bullets are undersized for the throats and too hard.

I would agree with using something besides Titegroup. I would also double check your measurements as the commercial bullets should be more like .358, and .359 wouldn't hurt.

noylj
August 13, 2013, 09:40 PM
Your bullets are too hard.
The bullets should be a tight slip-fit in the throats. Yours sounds like they are.
A 0.355" groove diameter sounds small, but that should NOT be a bad thing.
Don't use TiteGroup for lead bullets. It burns way too hot and can cause gas cutting with even perfect bullet-to-gun fit--which it really sounds like you have.
You would be better off with swaged lead bullets at a reasonable hardness or using any other powder. TG is marginal with lead bullets and a semi-auto, but not a revolver. Super hard bullets are marginal for a semi-auto, but not a revolver.
With your current bullets, get some Lee Liquid Alox and lightly tumble lube the bullets. Alox works great to prevent leading with a marginal bullet set-up. I put all my bullets in a large glass casserole pan on their sides, squirt in a little LLA, and shuffle/rotate the bullets around. They should all have a glossy/ shiny look. If not, add some more LLA. They should not be amber/brown. Don't worry if they are tacky. Tacky is aesthetically unpleasing, but the bullets will work just as well.
somewhere on the net there is a whole write-up about diagnosing leading problems with a revolver and lead bullets.
Fire lapping the throats may be needed if they are rough.
Finally, what is the cylinder gap? It should be 0.003-0.006".

rcmodel
August 13, 2013, 10:32 PM
Fire lapping the throats may be needed if they are rough.How do you 'fire lap' the throats without fire lapping the barrel too?

In which case, you would end up with what you started out with dimension-wise, only bigger all the way around.

Except with a giant jump on wearing the bore out even bigger by fire-lapping it.

rc

smovlov
August 13, 2013, 11:48 PM
I'm on my phone so it might be a little short. I slugged the bore. It measures .355. It's a 19-3. I'll do it again to double check. The bullets are from space coast bullets in Melbourne FL and say sized to .357. Bullets are a tight fit in the cylinder throat. Other powders I can get locally are WST, WSF, autocomp, AA 2, AA 5. The leading isint really that bad. I was just thinking maybe the throats were rough and needed reaming. Will a small amount of lead in the rear of the barrel affect accuracy that much? Ill start testing the loads out farther and see what happens then.

Thanks for the input

ljnowell
August 14, 2013, 01:38 AM
AA#2 is a fantastic powder for 38 special light lead loads. I load about 10k per year with it.

joneb
August 14, 2013, 01:54 AM
Should do like Fryxell says and fire lap the revolver?
If it aint broke, fix it till it is.

Jesse Heywood
August 14, 2013, 02:10 AM
I purchased Titegroup for lead in a revolver, mainly as a result of the advertising hype. I was disappointed. In the last 3-4 years I have tried 8 other powders in 38 with 158 gr lead, all had better results than the titegroup. Of the powders you mentioned I have used #2, with good results. My powder of choice for this is Red Dot.

Your bullet vendor doesn't list any hardness values, but they do show options for cowboy loads, which are .358 diameter. These should be softer, BHN 10-12, which should have less leading. You might want to check and see what the hardness values are.

StrawHat
August 14, 2013, 07:23 AM
...I slugged the bore. It measures .355...
What did you use to measure the slug?

Walkalong
August 14, 2013, 08:39 AM
I slugged the bore. It measures .355. It's a 19-3. I'll do it again to double check. Yea, seems tight, but never say never.
The bullets are from space coast bullets in Melbourne FL and say sized to .357. Bullets are a tight fit in the cylinder throat. A tight fit to the throats is good. By tight I assume you have to push them through.
Other powders I can get locally are WST, WSF, autocomp, AA 2, AA 5 WST or AA #2 should work well.
The leading isint really that bad. ................. Will a small amount of lead in the rear of the barrel affect accuracy that much?It will continue to get worse and move farther down the bore until accuracy is indeed affected and it will get harder to remove.

A nice stout, but max or below, charge of WST or AA #2 may cure the problem, if not, your bullets are simply too hard and you need softer bullet. Either that or you measured the bore wrong and the throats are smaller than the bore, but your probably OK there.

RugerBob
August 14, 2013, 10:42 AM
Either lead is to soft, or powder to hot, I have several 38/357s as do my other range buddies and most (with same issue) is due to soft lead.
Have you had any issues with jacketed? Maybe the timings off.

smovlov
August 14, 2013, 11:07 AM
What did you use to measure the slug?

I measured the bore slug with a set of dial calipers. The barrel is a five groove. I used two methods, by wrapping with shim stock (measuring and subtracting the stock), and by rotating the slug and checking the largest measurement. Both came out to .355. Ill do it again to double check.

A tight fit to the throats is good. By tight I assume you have to push them through.

They're pretty tight. I would probably have to push them through with a rod and a hammer. Ill check on that later too.

Titegroup burns clean because it burns hot. You can try two things: cut your loads and see if that reduces the leading or try 3.5 grains Bullseye with a 158 cast bullet in the 38 Special.

It seems that Bullseye is right there with Titegroup on the Hodgdon Burn Rate (http://www.hodgdon.com/burn-rate.html) chart. Why wouldn't it lead with the same bullet? Does it burn as fast just not as hot?

At 7 yards, you're just seeing how good a shot YOU are. You're pretty good. If you want to see how accurate your load is, you need to shoot at 50 yards, at least.

I was testing the loads at 7 yards because i wanted to take as much human error out of the equation as possible. The charges at the lower end didn't really shoot that well. I think my best groups were in the 3.6gr range for .38 and 4.7 for the .357. I already ladder loaded in .2 grain increments then went back to test .1 gr high and low. Is this a sound way of doing it?


Thanks everyone for your help. Ill get back with the rechecked numbers later.

smovlov
August 14, 2013, 11:38 AM
Just called the shop. They've got 231 and Unique. I know Unique is good for lead and 231/HP-38 is good in .38. Should I go with one of those over WST or AA#2?

Walkalong
August 14, 2013, 12:15 PM
Both are good. I would go with W-231 if you buy another powder, but I don't see it working any better than AA #2 or WST.

I shoot at through the chrono at 5 yards with a target at 7 yards all the time getting numbers. If it shows promise there I test it at a distance.

smovlov
August 14, 2013, 04:24 PM
Picked up the HP-38. The had both but I just grabbed what I saw first. Also got 1000 primers. I also talked to their caster and their loader. The caster said the bullets I have are an 8-9 on the Saeco hardness scale which from what I've read is almost Linotype. Pretty damn hard. He said the cowboys were softer lead. I'm just going to try the HP-38 and see if that works. I can use the TG in the .40.

AABEN
August 14, 2013, 04:38 PM
231 or AA-#2 Will do you a good job.

Lee Roder
August 14, 2013, 05:00 PM
I slugged the bore. It measures .355. It's a 19-3. I'll do it again to double check.

Seems tight too, but with an odd number of lands/grooves, the bores on S&W barrels are a little tricky to measure. You can't just whip out your dial calipers and measure the slug's diameter, directly anyway, after forcing it through the barrel.

Are you using precision shim stock?

smovlov
August 14, 2013, 05:38 PM
Are you using precision shim stock?

Not exactly. Cut up a aluminum can and measured it in several places. The measurement was very consistent and there were no burrs on the edges. I held it tight with some needle nose pliers and measured several times. I also got the same diameter by rolling the slug and taking the largest measurement. I'll do it again just to check and make sure.

ETA: http://www.lasc.us/brennan_saeco_table.htm

That's the conversion for Saeco hardness to Brinell. Looks like the bullets are between 13 and 17 in hardness.

rcmodel
August 14, 2013, 09:25 PM
I don't know how you are measuring it.

But I got a $100 bill here that says your S&W Model 19 does not have a .355" bore! :D

rc

smovlov
August 14, 2013, 10:05 PM
I don't know how you are measuring it.

But I got a $100 bill here that says your S&W Model 19 does not have a .355" bore!

If I didn't have so much to do tonight I'd slug it now! You've got me wondering now.

This is one method I used:

http://www.practicalmachinist.com/vb/gunsmithing/measuring-5-groove-slugs-189215/

Years ago an old millwright taught me to just roll the odd size slug between the slack jaws of a dial caliper and watch the needle go up and down. Keep rolling and the high number that repeats is the dimension.

The other method:

http://castboolits.gunloads.com/showthread.php?96999-How-to-measure-groove-dia-on-5-groove-bore&highlight=odd%20measure%20groove

To measure without specialized equipment:

# 1 Use a piece of flexible, but fairly stiff shim material (a strip of soda or beer can works well). Measure the thickness of the shim material and double this number.

#2 Wrap this piece of material around the slug and measure the diameter of the wrapped slug. Use a light touch with the measuring instrument, so as to not obtain a false reading.

#3 Subtract the measurement obtained in step #1 from the measurement obtained in step #3.

This gives you the groove diameter of the odd number rifled barrel.

Im not gonna bet against you. I'll measure soon. Got some cleaning to do around the house tonight.

Eb1
August 14, 2013, 10:39 PM
use something slower burning than titegroup.

ArchAngelCD
August 15, 2013, 12:30 AM
I also talked to their caster and their loader. The caster said the bullets I have are an 8-9 on the Saeco hardness scale which from what I've read is almost Linotype. Pretty damn hard. He said the cowboys were softer lead. I'm just going to try the HP-38 and see if that works.
Those bullets are best used for full power .357 Magnum loads. I would probably hunt out some bullets in the 5 SEACO range, similar to 10-12 BHN.

noylj
August 15, 2013, 01:51 AM
TiteGroup burns very hot. Try to hold a case that was just fired and compare to other powders. Must be a lot of NG in the powder.
The slug should be way oversized--I use .360 for .38s and 9mm. Look and see if the high spots look like they were actually dragged through the groove or missed it entirely.
Personally, a .355 groove diameter sounds pretty good for .38 shooting lead bullets.
In general, I found a 0.357-0.358" jacketed and a 0.359" lead bullet are pretty good universal sizes.
The SAAMI spec for .38 special groove diameter is 0.355" +0.004/-0.000", so 0.355" is in-spec.

smovlov
September 12, 2013, 01:40 PM
The good news is I'm consistent. The strange news is the barrel still slugs at .355". I used a lead fishing weight cast in an old .38 case. filled it almost to the top. Hammered it down a little. I got about .330" of engagement with the rifling. I also had a large ring pop off the top after the whole slug got in the bore so I know it filled the grooves. I measured two ways. One was with the aluminum can wrapped around the slug and the other was with rolling the slug in the calipers. I did the aluminum trick first and the rolling second. The calipers are Mitutoyo 505-101 from the 70s. The measurements were within .0005 of each other.

I double checked the bullets and they are uniformly .357" which is what is marked on the box. I asked at the shop why (where they cast and size them) and I don't remember getting a clear answer.

I picked up some HP-38 and loaded some up but haven't gotten the chance to shoot yet.

The slug also slips through the chamber throats without resistance. A bullet will not slip through. My guess is the throats are around .356".

Does anyone have a V-Block Mic? I really want to see if I'm messing up here. I know its within SAMMI spec but it just seems weird.

I'm in grad school now so that's why I haven't updated anything. Busy busy busy. Thanks again for all the help!!!

USSR
September 12, 2013, 01:54 PM
smovlov,

Doesn't really matter what your barrel dimensions are, lead bullets will easily slug down to what they need to be. Instead of doing all this measuring and remeasuring, just get yourself some bullets sized at .358" made of an alloy with a BHN of < 10.

Don

Arkansas Paul
September 12, 2013, 02:20 PM
^ Do like Don said.
Your bullets are either too small or too hard, or maybe both.

918v
September 12, 2013, 03:09 PM
R U measuring with the thin or the thick part of the caliper jaws? If the thin, then you are gonna have errors. I also think your barrel is .357" and your throats .358". It might be slugging smaller due to a constriction near the forcing cone, though. Can u feel one?

A soft bullet will overcome this cuz it will obturate past the constriction. Also, if you cast your own, use the NRA 50/50 formula. It's better for target loads than commercial lubes.

smovlov
September 12, 2013, 03:39 PM
R U measuring with the thin or the thick part of the caliper jaws?

I am measuring with the thick part of the calipers. I couldn't discern a constriction before the forcing cone. Not saying there is not one, I just cant feel it.

Your bullets are either too small or too hard, or maybe both.

Bullets measure out to .357". Probably too hard for .38 velocity.

Instead of doing all this measuring and remeasuring, just get yourself some bullets sized at .358" made of an alloy with a BHN of < 10.

I feel ya Don. If I cant get them to shoot right out of the .38 Ill reserve the ones I have for .357 loads and get some wadcutters for the .38.

Everyone keeps telling me its not .355" so I feel like I'm doing something wrong. Just trying to see if its the gun or me. I have plans on shooting lead out of a few guns so I'm trying to check my methods and get everything right.

Thanks for the input everyone.

918v
September 12, 2013, 05:48 PM
I am measuring with the thick part of the calipers. I couldn't discern a constriction before the forcing cone. Not saying there is not one, I just cant feel it.

If you can't feel it then you prolly don't have one.

Try the softer bullets and the 231. Should solve the leading problem.

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