Tuning up a revolver for lead.

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smovlov

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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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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.
 
From what I can read my barrel slugs out to be .355.
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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.
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That would be highly unusual too, considering lead bullets for a .38/.357 should be at least .358".

rc
 
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.
 
I also get lead in the cylinder throats.
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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.
 
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".
 
Fire lapping the throats may be needed if they are rough.
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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
 
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
 
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.
 
I slugged the bore. It measures .355. It's a 19-3. I'll do it again to double check.
Click to expand...
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.
Click to expand...
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
Click to expand...
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?
Click to expand...
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.
 
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.
 
What did you use to measure the slug?
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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.
Click to expand...

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.
Click to expand...

It seems that Bullseye is right there with Titegroup on the Hodgdon Burn Rate 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.
Click to expand...

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.
 
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?
 
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.
 
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.
 
smovlov said:
I slugged the bore. It measures .355. It's a 19-3. I'll do it again to double check.
Click to expand...

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?
 
Are you using precision shim stock?
Click to expand...

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.
 
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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
 
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!
Click to expand...

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.
Click to expand...

The other method:

http://castboolits.gunloads.com/sho...on-5-groove-bore&highlight=odd measure groove

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.
Click to expand...

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