Seating depth for Lee C358-158-SWC?

[jfvacc]

Hello everyone. I am fairly new to casting and I have this mold. I intend to cast for both magnums with gas checks and .38s without the checks. One concern I have is the crimp groove location on the mold. According to the .38 and .357 Magnum load data I have, if I use the crimp groove I will be under OAL by a few hundredths. This seems like a lot to me.

Does anyone have experience with this mold? I know I can reduce the powder charge to compensate for the increased pressure...but I am wondering if pressures will be safe with starting loads if I use the crimp groove?

[Recluse]

I have the Lee TL158SWC mold--it's my number one top shooting boolit out of my entire inventory.

I seat it in .357 at 1.635, and in .38 Special at 1.415 and use a roll crimp on both.

:coffee:

[jfvacc]

That's the tumble lube mold, yes? I considered that one but wanted the ability to use gas checks for some .357 loadings.

[Recluse]

That's the tumble lube mold, yes? I considered that one but wanted the ability to use gas checks for some .357 loadings.

Yep. I liked the design of the boolit so I bought the mold in a two-cavity. I've never needed a gas check for anything .357 magnum. I even load that tumble-lube boolit up to some pretty hot velocities and get zero leading.

:coffee:

[mdi]

For the O.P. If the bulet you're talking about does have a crimp groove, just use that to determine the OAL. The bullet is designed with the location of the crimp groove in mind considering case volume and OAL. I can't remember the last time I measures OAL for any of my revolvers. I cast three different bullets for my .38/.357 and four bullets for my .44s (Mag. and Spec.). I also have one mold each, .357" and .430", with tumble lube grooves and I seat them on the third groove from the top (which gives me about the same case capacity as a standard groove bullet of the same size). I rarely use gas checks as I size the plain base bullets to cylinder throat diameter and have very little/no leading even at magnum velocities...

[Charlie Two Tracks]

Hi jfvacc. Do some serious reading about these cast boolits on this site. I came hear awhile ago with all kinds of information about cast............. most of it was wrong. Cast boolits out of a .357 will go over 1400 fps. Some a lot more. No gas checks. This site has changed how I shoot cast and it has all been for the better. You may use gas checks but you may find out that you don't need to. They kept saying that fit is king and they were right. Welcome aboard and have some fun. You are in for a great time.

[Tim357]

This boolit does seat deeper in the case than other boolits of same weight. Stick to the adage to start with STARTING charges for loads, then if YOUR gun shows that particular load is safe, then move up the charge a bit at a time. If you start with a borderline max load, then aggravate it with a deep-seated bullet, you could be asking for trouble.
my two cents
Tim sends

[jfvacc]

Thank you all. I will start with the starting loads and seat to the crimp groove.

[williamwaco]

Hello everyone. I am fairly new to casting and I have this mold. I intend to cast for both magnums with gas checks and .38s without the checks. One concern I have is the crimp groove location on the mold. According to the .38 and .357 Magnum load data I have, if I use the crimp groove I will be under OAL by a few hundredths. This seems like a lot to me.

Does anyone have experience with this mold? I know I can reduce the powder charge to compensate for the increased pressure...but I am wondering if pressures will be safe with starting loads if I use the crimp groove?


I use this bullet exactly like you describe no gas check for .38 and mild .357. with gas check for moderate .357. ( I never load really hot )

I have pushed this bullet to 1675 fps in my Winchester 92.
I size .357 and lube with Lyman 50/50 Alox/beeswax.

I agree that you do not need the check for the milder loads but I get better accuracy with the gas check installed in all loads.

I have no leading with or without the check.

[jfvacc]

I am starting with 3.0 grains of Bullseye seated to the crimp groove. OAL is 1.405", give or take a thousandth. Lube is a light coat of Lee Alox and they are sized to .358 with a Lee sizing die.

For comparison, Alliant's 2004 data shows a max load of 158 gr LSWC under 3.6 gr of Bullseye at 1.42".

I feel that I should be fine with 3.0 grains. I will try those and if necessary, work up to 3.2 gr of Bullseye.

Mostly I'm paranoid about wearing out a somewhat collectible gun. I'll be shooting these mostly through a very nice Colt Commando, though my Ruger LCP and GP-100 will get a few as well.

[fecmech]

I would suggest you measure the distance from your crimp groove to the base of the bullet. Then you will know how much case capacity you are using up with that bullet. If you post the measurement here we may be able to ease you mind by comparing to another bullet of the same weight and case capacity which has more extensive load data.

[jfvacc]

It's tough to measure, fecmech. Near as I can see, the gap from the top of the crimp groove to the base of the bullet is .406".

[ku4hx]

A gas check may or may not improve your accuracy, that's likely to depend on your particular gun and the load(s) you develop.

As to needing a gas check, I haven't used one with .357 Magnum top loads in decades. As long as I use an appropriate lube and get them properly sized for my guns I have no leading.

I store my gas checks (Hornady and Lyman) in their original 20-30 year-old boxes. Still got almost all of them too. When my son, or daughter, inherit them they may have a different opinion.

I've never worried about OAL for any of my revolver loads. Always seat the bullet to the crimping groove such that when crimped the bottom of the first driving band just touches the mouth of the now roll-crimped case. As long as the loaded cylinder rotated freely when in the firing position I was set to go. Of course I always followed accepted load data by reputable sources and worked up from the starting load.

[fecmech]

It's tough to measure, fecmech. Near as I can see, the gap from the top of the crimp groove to the base of the bullet is .406".

The Lyman 358156 is very close to that, mine measures approx .410 from the top crimp groove to the base so it will have a hair less case capacity than your Lee. This applies to Lymans .38 spl and .357 load data for 358156. Your oal with the Lee will be shorter due to a shorter nose but you will have a tiny bit less in the case than 358156 which is the important part. If I had that bullet I would use the data for 358156 and not worry a bit.

[williamwaco]

A gas check may or may not improve your accuracy, that's likely to depend on your particular gun and the load(s) you develop.

As to needing a gas check, I haven't used one with .357 Magnum top loads in decades. As long as I use an appropriate lube and get them properly sized for my guns I have no leading.

I store my gas checks (Hornady and Lyman) in their original 20-30 year-old boxes. Still got almost all of them too. When my son, or daughter, inherit them they may have a different opinion.

I've never worried about OAL for any of my revolver loads. Always seat the bullet to the crimping groove such that when crimped the bottom of the first driving band just touches the mouth of the now roll-crimped case. As long as the loaded cylinder rotated freely when in the firing position I was set to go. Of course I always followed accepted load data by reputable sources and worked up from the starting load.


+1 on every word. BUT I do find slightly smaller groups at 50 yards with the 158gr Lee gas check bullets over the Lee 158 gr bevel base tumble lube bullet. slightly means like 1.00 vs 1.25 inches on average. Thompson contender 12" with 8x Weaver scope.

[jfvacc]

The Lyman 358156 is very close to that, mine measures approx .410 from the top crimp groove to the base so it will have a hair less case capacity than your Lee. This applies to Lymans .38 spl and .357 load data for 358156. Your oal with the Lee will be shorter due to a shorter nose but you will have a tiny bit less in the case than 358156 which is the important part. If I had that bullet I would use the data for 358156 and not worry a bit.Thank you very much!