358429 and the GP100

[theperfessor]

There have been several threads on this posted on this forum over the years, but as we get new members and old members try different things, this topic seems to pop up. I was recently pm'ed by a member who asked about a statement I made in which I stated that a 358429 crimped in the crimp groove does not fit in my GP100. It does fit in my Blackhawk with no problems. It's an overall length problem.

Over the years both Ruger and Lyman have established/allowed certain lengths and length tolerances of their respective products to vary. Certain combinations of these two products just won't fit. I have taken pictures of (a) my sample .357 mag cartridge w/a 358429 bullet from my 4 cavity Lyman mold, (b) the rim thickness of the sample case, and (c) my GP100 cylinder length.

Here are the dimensions:
COAL of sample case = 1.674"
GP100 Cylinder length = 1.612"
.357 mag rim thickness = 0.053"
Max length to fit GP100 = 1.612" + 0.053" = 1.665"

Note that the .357 mag sample case is 0.009" longer than the max for the GP100. Given the slight clearance at recoil shield/case rim interface at the rear, and the barrel/cylinder gap at the front, the sample case just slides between the barrel face and recoil shield. The gun won't cycle smoothly with blanks, and if the recoil causes a bullet to pull out slightly the gun would be totally tied up.

I note that the cylinder length of my New Model Blackhawk is 1.640", and with a rim thickness of 0.053" it permits a COAL of 1.693". I reserve using the 358429 crimped in the crimp groove in my Blackhawk, and use the 358429 in .38 cases in my J and K frames and GP100. I use the 358477, 358156 or any of several other 150-160 gr bullets in .357 in my GP100.

I know a lot of folks will suggest trimming back .357 mag brass to work, or crimp on the drive band instead of in the crimp groove, or use .38 cases for .357 mag level loads. All workable ideas, with various drawbacks. I just prefer to do otherwise. Since I only have two .357 mag handguns, and the most used load in my Blackhawk uses the 358429, its pretty easy for me to match ammo to gun when I grab a box and head out the door.

[Lefty SRH]

I've run into the same problem with my GP100 when I load the Lyman 358311. The OAL is 1.590, in order to get that OAL I have to crimp over the front band.

[btroj]

My GP100 will allow a 358429 to load and fire must fine. I probably am using a different era mould with different dimensions. Who knows how many variations of the same mould Lyman made over the years.
My GP100 will not allow me to shoot the Mihec 359640 at all. Total cartridge length isn't the issue, it is the live on the bullet. It hits the shoulder in the front of the chamber that becomes the chamber throat. I could probably size the bullets smaller and get them to fit but I use a 359 sizer for everything else and don't want to change.

Amazing how a few thousandths of an inch can change what does or doesn't work.

[fecmech]

My GP and 358429 will just barely work in the crimp groove if I really roll a super heavy crimp into the groove. That cracks cases quickly so I've gone to a light taper crimp and an oal of 1.638. I chrono'd both 2400 and 296 using taper and roll crimps and found NO difference in ballistics and case tension prevents bullet pull. For me Win/Win.

[Mk42gunner]

My GP100 will allow a 358429 to load and fire must fine. I probably am using a different era mould with different dimensions. Who knows how many variations of the same mould Lyman made over the years.
...

Amazing how a few thousandths of an inch can change what does or doesn't work.

My current 4" GP-100 from about 2002 and DC 358429 mold from who knows when work together too.

I have an older Ideal SC 358429HP that I just realized I haven't tried. There is my project for later this week.

Robert

[theperfessor]

I suspect the "size drift" is more of a Lyman problem than a Ruger problem. Several members here have posted photos of various popular Lyman bullets with the same four/five/six digit designation that are remarkably different in key areas. Always makes me wonder which bullet their loading data is based on!

[9.3X62AL]

One could get the impression that Lyman moulds are like Duesenberg automobiles......no two are alike! :) To be fair to Lyman and Elmer Keith, whose design #358429 is.......it was originally intended for use in 38 Special revolvers, where its long-nosed design specs (to create powder space in the 38 Special casing) fit most revolvers of the time.

Many times, once the design history of a given mould/casting is understood its quirks and foibles come into context and can be dealt with by the modern ammocrafter easily.

[EDK]

Uncle Elmer designed his boolits for 38 and 44 SPECIAL, not MAGNUM. The 357 cartridge was derived from the 38/44 factory loads used in heavy frame SMITH & WESSONS...loads that would never exist in today's lawyer ridden society! S&W compounded the problem by not making cylinders longer in the Model 27, 28, etc; they saved a few yankee dollars and were cursed soundly over the years!

358429 loaded in the crimp groove can also be problematic in various lever action rifles in 357...one of those things you have to try in your gun and then adjust the gun or ammo to get the results you want. You determine whether it is a PITA or a challenge to over come.

:redneck::cbpour::guntootsmiley:

[paul h]

I've been thinking of adding a GP-100 to accompany my 357 blackhawk but want ammo that can be run through both guns. Out of curiosity, do S&W 686's also have short cylinders?

[9.3X62AL]

I did a "tale of the tape" with my castings of #358429, and found that my bullets' noses extend about .375"-.400" forward of the crimp groove (top and bottom). Given "worst case scenario" using brass with a length of 1.285", this will yield a cartridge OAL of 1.660" to 1.685".

My 1990-vintage S&W 686 x 4" has a cylinder length of 1.625". Add on about .050" for rim/casehead clearance (the charge holes are not recessed) and you come up with a figure of 1.675". It appears that in my revolver I will need to seat bullets a little deeper into the crimp groove to assure clearance while the cylinder clocks through. It's very close, in other words.

[theperfessor]

I find the 358477 or if you don't mind GCs the 358156 work well in both my GP and my BH.

[DrCaveman]

I have a single cavity Ideal 358429.

I don't have the length measurement in front of me but it works fine crimping in crimp groove with 357 mag cases in both my g100 and smith m19. Maybe I am a few thousandths shorter than I could be while still being 'in the crimp groove' but I definitely am not crimping on the front driving band.

I have heard agreement about this from various sources: gp100s, m19s, 586/686, Blackhawks have long cylinders. Can tolerate 358429 crimped properly. M27/28 and prob a bunch of others are too short and you must crimp in front of first driving band.

But if your 358429 is sized a little different then all bets are off. My main point is that 358429 'should' work fine in a gp100 as long as the primer is fully seated and boolit has no nose fin.

[PacMan]

I have a Noe 358156 GC that is very accurate in my two GP100s.
Best shooting bullet i have as a mater of fact.

[sixshot]

The old #358429 is one of the all time most popular cast bullets ever designed but as the Professor metioned it won't work in some sixguns using 357 mag cases. I've never felt undergunned using that slug in 38 special brass & 13.5 grs of 2400 & I've shot tens of thousands of them. If I need a bigger hammer I move up to the 44 special.
The #358477, #357446 & the excellent #358156 Ray Thompson GC are all dandy moulds that have been around for many decades & work fine in almost all sixguns. The dual crimp groove is a big help if you are short on magnum brass & have lots of 38 special brass like most of us.
The GP100 is a dandy sixgun, rugged as an anvil!

Dick

[GP100man]

Fellas the nose is long & Mr. Keith raised Holy Heck to keep it the same length as the 429421 (& yes I checked almost as soon as I read this) I think most problems occur from inconsistent brass length as most don`t trimm revolver brass.

All mine are 1.179 & I have .020" from nose to cyl face .

[PacMan]

Fellas the nose is long & Mr. Keith raised Holy Heck to keep it the same length as the 429421 (& yes I checked almost as soon as I read this) I think most problems occur from inconsistent brass length as most don`t trimm revolver brass.

All mine are 1.179 & I have .020" from nose to cyl face .


I am waiting on a Keith Mold from LBT and Ballistic Cast so i have nothing to work with yet but i have a tendency to agree backed by nothing at this time.
Time will tell for me.

[Beagle333]

:popcorn: Apparently the jury is still out on this one.


(I'm just gonna have to buy one and find out.)

[GabbyM]

:popcorn: Apparently the jury is still out on this one.


(I'm just gonna have to buy one and find out.)

Well it's not an opinion. Bullets either fit or they don't. That's why any laoder owns a calipers.

I've the NOE mold copy #358429. Very nice.
Tried to get a Lyman 358429. However the first mold was woefully undersized and when I sent it back to Lyman they sent back another that was even worse than the one I'd returned to them.

[PacMan]

Fellas the nose is long & Mr. Keith raised Holy Heck to keep it the same length as the 429421 (& yes I checked almost as soon as I read this) I think most problems occur from inconsistent brass length as most don`t trimm revolver brass.

All mine are 1.179 & I have .020" from nose to cyl face .


1.179 length is for .357 mag?

[TCLouis]

I have been loading and shooting a bunch of 358429's recently in all of my 357s with no problems crimped in the crimp groove. . . .

I just realized these were cast in the 358429 Group Buy mold.

Wasn't it modified to fit "all" Cylinders?

Now I think I know why I could not tell them from 358156s when I put them down together.

I'll be the first to admit that I am too lazy to go down and compare them right now.

[PacMan]

I have a Ballistic Cast Keith on order along with one from LBT.The LBT will have a .37 nose which i know will fit my GP100.
Had the LBT mold cut with a GC. I know,i know i should be hung and shot but i'll bet good money it will out shoot a standard Keith at max velocity.
Time will tell for sure.

[theperfessor]

I posted (w/ pictures) the dimensional data for my particular gun and loaded cartridge. Fecmech shared some data also.

Anybody care to post dimensional information on your GP100 and Lyman brand 358429 load? Pictures not necessary, just the ability to accurately read your caliper or micrometer.

I'd be interested in comparing how much the Lyman 358429 and the GP100 cylinder length have changed over the years. Feel free to post if you're using a non-Lyman mold, just let us know that.

Edt to add: Sorry to not acknowledge that 9.3x62Al also posted some numerical data here, I missed it one first read through to catch up to thread. Since one of the few problems that can occur to a revolver is cylinder tie-up from a bullet coming loose from recoil, I won't shoot loads that are "close" to the same length as the cylinder.

[GP100man]

To correct my mistake the case max on 357 magnum is 1.290

My Lee trimmer trims to 1.279

My 358429 OAL is 1.640 (measured 5 & averaged , but only a variance of .003)

My 358156 HP OAL measures 1.570

My 4" GPs cyl is 1.610 measured from where the case head spaces from to cyl face.

[Beagle333]

I tried out a few of my newly minted 358429s this morning, and found that my bullet noses extend about .383±" forward of the crimp groove as well. And with my brass, which is running 1.280-1.284", mine come out to be 1.663" to 1.667". A couple of em did let the cylinder rotate,.... but it's just too close for comfort. So - - - .38 brass it is!! :mrgreen:

[armexman]

Yesterday afternoon went and shot 357 with 358429 seated slightly over SWC edge, loaded with load of AA9 from book and now have a two laser guns in my house. I was very happy with MY results, so much so, that some winter testing and I may have my 357 load for life! Boolits sized at .358 and lubed with Lars 2500. Tiny roll crimp, enough to chamber in both 6"-ish revolvers, and with nickel cases. I will take pictures and try to post them soon.

[brghp]

Another fine bullet would be Lyman's 358665 which weighs in at around 164 gr with WW.

[theperfessor]

Can't argue with that!

[GLL]

Keith:

Will you and your students be making lead hammers this school year?

Jerry

[theperfessor]

Probably, if enough people want one. I thought the market was a little saturated for a while, but I will go ahead and post a thread this week to see if anyone is interested.