357 cartridge diameter issue - help please

[magnumb]

While a long-time shooter I am pretty new to reloading. I am experiencing an issue reloading 357s (and 38s). I am using Missouri bullets 158 grain 357s. The measure exactly .358 diameter. I am using a roll crimp, at least for now. The roll crimp is set on a lyman die for about 3/4 a turn past where it would touch the case. I am seating the bullets about mid-point (maybe a tad bit higher) of the crimp groove.

The resulting reloads are just a little sticky (before firing) going into my S&W model 19. At things have it, after firing it can be very hard to rotate the cylinder, and have to use a brass rod to extract cartridges, even though they should not be over pressure. I bought a Hornady cartridge gauge, and they are just a little bit more snug going into it. I assume they should slide in the whole way with not extra assistance, and when inverted, just drop out.

Measuring the case diameter I was getting .378-.380. I went back and applied about another 1/4 turn of roll crimp, bringing then down to .377-.379.

The SAMMI case spec is .379, My gauge seems to measure .377, tighter than the max spec.

Measuring the components (the best I can) the boolit is .358, the brass wall thickness is .011 +.011. adding all this up we arrive at 0.380, which exceeds the .379 specification and definitely my .377 case gauge.

So that's my story, now for the help part.

1) What finished diameter should I expect to measure with a .358 dia boolit?

2) I also have a taper crimp in my lyman set. Can I re-crimp with the taper die to bring these in spec? I have about 50 rounds I would like to salvage if possible.

3) Is there something I might be doing wrong with my roll crimp? How high up the crimp groove should I seat, HOw many turns on the crimp die?



Appreciate the help from you experienced reloaders!

Marc

[Ben]

Load one round with only enough roll crimp to allow the round to chamber. Report back.

Ben

[Silvercreek Farmer]

What brand brass are you using?

[Recycled bullet]

Go through your brass stash pick all the same head stamp. My recommendation is rp brass for cast boolits. If it's all brass that you have fired in that gun all the better

1) Resize/deprime . Back off the die maybe a turn to still remove the old primer, size the brass less aggressively. Check that the empty resized cases fit the cylinder.

Neck tension is set here with the sizing die.
Cast bullets are slightly oversized and do not require as much neck tension as jacket bullets.

2) Expand the case mouths to accept the bullets with out scraping. I use a lee universal expander.

Discard any brass that splits mouths.

3) Prime the cases however you like make sure the primers bottom out in the primer pocket and are below flush the case head.

4) Dispense powder.

5) Seat bullets. Spin the bullet seater all the way in/ down and run the die base all the way out. The idea is to isolate the process of seat/crimp and prevent coating scraping or casing buckling.

Coating scraping buildup/buckled brass is ugly and prevents free chambering.I seat the bullets to really close to the crimp groove.

6) Crimp all the cases. Back out the seater crimper die and back out or remove the bullet seater stem then with the ram all the way up with a seated cartridge spin the crimp die down using your fingers until it is not possible to tighten it further. (With finger tightness not with tools ok)

Back the ram down slightly then start with adjust the crimp die one quarter turn tighter and inspect the completed cartridge. Adjust crimp as needed to help cartridge feeding.

Take it and drop it into the revolver cylinder and see if it falls out under it's own weight when you tilt it up. This is the plunk test .


What powder charge are you using and what loading books are you reading?

[Recycled bullet]

And make certain the cylinder is spotless clean. The revolvers cylinder is your case gauge.

[Jim22]

That sounds like an awful lot of crimp. Over crimping will cause cases to bulge and be difficult to load. Ben has it right above.

Jim

[Recycled bullet]

It should look like this and fall into and out of the cylinder under it's own weight.https://uploads.tapatalk-cdn.com/20230212/b3f6caf28426c3a964b309e2e62953ca.jpg

[lar45]

As was stated above, seat the bullets, then crimp the bullets.
Sometimes you can expand the cases or buckle them slightly when seating and crimping at the same time.
I seat the bullets towards the top of the crimp groove, then roll crimp enough to roll the case mouth into the crimp groove. For top end magnum loads in heavy calibers, or for super heavy bullets, I use a more aggresive roll crimp to hold everything in place.

Check your cartridges for fit at each step of the process to see where the problem is.

[DougGuy]

SAMMI calls for .381" at the case mouth. With Starline brass at .011" x 2 that still leaves you .359" so you shouldn't have interference in the chamber.

You MAY be experiencing interference at the cylinder throat. Typically a S&W cylinder will take a .357" Pin, most will be very tight on a .3575" pin or not take it at all, and the majority would need throats honed to use a .358" boolit without interference.

[BK7saum]

That sounds like an awful lot of crimp. Over crimping will cause cases to bulge and be difficult to load. Ben has it right above.

Jim

2nd this. You are most likely crimping too much and bulging the case.

Adjust your crimp so that you get a little roll. It doesnt take much.

[Silvercreek Farmer]

Size an empty case, does it drop in? Load a dummy with no crimp, does it drop in?

[NSB]

Sounds like way, way too much crimp. You don’t need much crimp at all to keep the bullets from moving in the case when the gun fires. If you’re going 3/4 turn after the case mouth hits the inside of the die you’re way too far. I’d suggest 1/8 turn and see what happens. If you can easily see your crimp, you already have too much.

[243winxb]

To much roll crimp, bulges shoulder. Taper crimp to fix.

[fredj338]

I dont measure crimp i use a case gage or the cyl. Check case length too, you could be a bit long for your cyl.

[MarkP]

Are you experiencing this with 357 Mag and 38 SPL's? Or just with 357 brass?
When measuring the mouth diameter hold up to a light and look to see if the crimp is larger in diameter than the side of the case. (Slight bulge)

[magnumb]

I will first try the fit after resizing. things will only get worse after expanding and crimping a 358 bullet. Next I wiil try a very light roll crimp, starting at 1/8 and progressing up to see if adding too much crimp is causing the issue. Adding even more roll crimp (1 turn up from 3/4 did not make things better). I guess I will try to salvage using using my taper crimp to see if I can reduce. I have not tried these in my marlin 1894, I don't know if that chamber will be as tight or maybe tighter. Don't want to get a round jammed in my lever action, might be even harder to extract. Thanks for the suggestions I will report back.

I was also thinking of just using my taper crimp (hornady AP press) as a second stage and using the seater for seating only. Seems most reloaders are using a roll crimp when they have a groove. Strikes me odd that many other high pressure cartridges use a taper crimp, hard to understand why this is frowned upon so much for 38/357? not tradtional for sure.

[magnumb]

I had just a few issues with 38 as well. from another web video, it looks like I should back off the crimp die a full turn during seating , dont want to cause any buckling during seating. I am using the Lyman M expander btw.

[Ben]

Did you ever try this ?

Load one round with only enough roll crimp to allow the round to chamber. Report back.

[45DUDE]

Make sure the cylinder is not rubbing the forcing cone. The boolits need to fit the case gauge easy. I full length resize.

[mehavey]

- Seat the bullet -- without any crimp -- to where the case mouth is at fully 3/4 of the way into the crimp groove
- Unscrew the seating stem
- With the ram fully raised, screw the seating die down to contact
- Drop the ram, screw in seating body 1/2 turn,* raise the ram and crimp the bullet
- Screw seating stem down to firm contact w/ bullet
- Lock everything down at that point....

.. . . Done... Good2Go from the point on to seat/crimp in one stroke w/o bulging the case


*Maybe 2/3 in a pinch depending on comment/conditions below

And yes, heavy-recoiling revolvers need of good roll crimp to keep other bullets in
the cylinder from progressively walking out of the case as the gun is fired....

[Bigslug]

Plenty of good advice here. I'll add one experience of mine:

The 175 grain Ranch Dog from NOE has a nearly 0.1" long front driving band surface. As a tumble lube bullet, it's whole purpose in life is to avoid the sizing die process, so it stays at the as-cast diameter of .360". In my Smith & Wessons - no problem. In my Ruger DA's, the throats are 0.030" to 0.050" shorter and I have to run them in .38 brass to get them to reliably chamber.

In my case, there's a length AND diameter component to the problem, and at .358" you SHOULDN'T be running into this, but my Ruger's throats ARE .357" (The Smiths are .358"). You might see if a sized bullet can be pushed far enough to pass the point it would be sitting when loaded in the cases.

[magnumb]

I do believe I was applying too much roll crimp. The Missouri bullets 158 has very tiny/shallow crimp groove. Even a slight bulge below the roll crimp is enough to cause issues. The groove is so fine, I might consider use using the first die to seat bullet (no roll crimp), and using the second die to taper crimp. I don't know if my boolits will creep with only a taper crimp?

The good news I was able to salvage all but a handful of rounds by subsequently applying a taper crimp (about 3/4 turn on my lyman die). This was just enough to make my loaded rounds useful.

If you do the math (I'm confused) these rounds should not fit. .358 bullet plus .011 plus .011 for brass equals .380. The cartridge is specified to be .379 max.
My cartridge gauge does not like them to be more than .377, and .378 has trouble fitting. My model 19 will take the .378 rounds. I have the feeling I am actually compressing the size of the Boolit, which may hurt accuracy? I measured a number of factory rounds (they fit gauge easily), They were around .376 to .377 max. Most were jacketed, but even Buffalo Bore 158 outdoorsman (Hardcast) measures .376.
I'm measuring brass at .011 thickness, but maybe that's not accurate?

[mehavey]

Don't taper crimp a 357 Mag/Revolver.
The bullets will walk from the case mouth.

If the crimp groove is too shallow, go ahead
and roll-crimp in a 2nd step after seating.

[Silvercreek Farmer]

What brand brass are you using? It is very possible that your brass is too thick for cast boolits, but would work fine for a smaller jacketed bullet.

https://castboolits.gunloads.com/showthread.php?394161-357-PPU-brass-a-warning

If you can’t get a roll crimp to work, you might consider the Lee Collet Crimp. Squeezes from the sides instead of pushing down on the case.

https://www.titanreloading.com/product/lee-357-magnum-collet-style-crimp-die/

If all else fails and you just want to dispose of the rounds without pulling them down, a Lee Factory Crimp die has a carbide ring that will squeeze the round down to specs. Might lead your barrel as it would squeeze the boolit down, might not.

[243winxb]

Taper or roll crimp.
Neck tension keeps bullets from moving under recoil. Measure case outside diameter before & after seating bullets. The OD, after seating, should increase by .002" minimum, for good bullet hold.

A taper die may size a lead bullet smaller in diameter, if over used. Avoid soft alloys. BHN 15 best.

Test- fill cylinder, shoot all but last round. Has bullet moved forward, out of case. If yes, a smaller expander may help.

Revolvers are best with a roll crimp.

[mehavey]

If all else fails and you just want to dispose of the rounds without pulling them down. ..
just run them partially into the sizing die... just enough so they smoothly chamber again in the cylinder.

So easy, a cave person....
:drinks:

[bruce381]

roll is crimp is fine BUT make sure cases are trimmed to same length. There are always a few that are long they will OVER crimp and bulge and be the sticky ones. I trim all my brass ONCE to minimum length then going on no more trim is needed.

[DougGuy]

If you do the math (I'm confused) these rounds should not fit. .358 bullet plus .011 plus .011 for brass equals .380. The cartridge is specified to be .379 max.
My cartridge gauge does not like them to be more than .377, and .378 has trouble fitting. My model 19 will take the .378 rounds. I have the feeling I am actually compressing the size of the Boolit, which may hurt accuracy? I measured a number of factory rounds (they fit gauge easily), They were around .376 to .377 max. Most were jacketed, but even Buffalo Bore 158 outdoorsman (Hardcast) measures .376.
I'm measuring brass at .011 thickness, but maybe that's not accurate?

Do you not read anyone else's contributions to your thread?


SAMMI calls for .381" at the case mouth. With Starline brass at .011" x 2 that still leaves you .359" so you shouldn't have interference in the chamber.

You MAY be experiencing interference at the cylinder throat. Typically a S&W cylinder will take a .357" Pin, most will be very tight on a .3575" pin or not take it at all, and the majority would need throats honed to use a .358" boolit without interference.

According to YOUR math, and my experience with hundreds of 357 mag cylinders, your boolits SHOULD fit. I think you are letting the cartridge gauge confuse things. Have you tried pushing any of your boolits through the cylinder throats from the front?

[magnumb]

I read every comment, trying to learn from others with more experience! Sorry I did not respond directly to yours. I looked but could not find a SAAMI drawing for a case mouth (Are we talking about the hole in the cylinder? The cylinder throat?) I have about 4 reloading manuals, but they all say .359 for the cartridge, but not data for hole in the cylinder (throat).
I bought Hornady cartridge gauges. They seem to be about .357 or 358 (seems tighter than spec). Cartridges that won't drop in the gauge will mostly drop in my model 19 cylinder. I will have to ask Hornady, these may go back. I just did not want to have an expensive clean nickel revolver banging around on my bench every time I reload.

[DougGuy]

The chamber is where the cartridge sits. At the end of the chamber is a chamfer, the parallel smooth bore in front of the chamfer is the cylinder throat.

My bad you caught me making a mistake quoting SAAMI, it does indeed say that the chamber spec is .380" at the end. BUT.. I have pinned out a LOT of cylinders, and 90% of them will accept a .381" ZZ minus pin gage all the way to the chamfer. Both of the 357 finishing reamers I have here mic at .381" at the end of the chamber.

99% of the issues with a 357 cylinder involve tight throat diameters, which will cause interference while trying to chamber a round, IF the boolit ahead of the case is larger than the throat. This is why I asked if you have tried to push one of your boolits through the cylinder throats from the front.

[Forrest r]

A picture of the throats in a cylinder. What the picture is supposed to represent is moving the bullet out further/longer oal aiding in accuracy.

https://i.imgur.com/Lcmp4hk.jpg

In the picture you can clearly see a "step" then the chamber angles down to a smaller diameter. This is the leade/throating of the chambers in your cylinder.

[mdi]

I'm with Ben on this issue. Without going into specs to the thousandths of an inch, try a dummy with the case just deflared, very little crimp.