38-55 Six Cavity

**Tom Myers** · 01-03-2006, 10:42 PM

In a previous thread titled "What Group Buys are Open NOW?" some ideas and a couple of images were posted concerning the feasibility of a 38-55 6-cavity group buy.

After a little research and input from other forum members I added it all up, divided by Zip then multiplied by Squat and arrived at a few conclusions (mine only and subject to suggestion and change) that suggested another 38 caliber bullet dimension sketch.

Some of the conclusions:
1. We are working with three different chambers that could use the bullet in consideration:

A. The old, long, Ballard taper crimp chamber (my version is 2.140" long) which will chamber brass with a nominal length of 2.135" with no throat only a 15 degree leade angle to the bore.

B. The new short version (Clymer's Reamer specifications show 2.119" chamber length) again, only a 15-degree leade angle to the bore.

C. The 375 Winchester chambering which is (from memory only) 2.035" with a throat (I don’t know the length of it).

2. Next, we have three different lengths of brass that will or will not fit in the above chambers.

A. 2.130" 38-55 brass that will fit only in the older chamber.

B. 2.075” 38-55 brass that will fit in either the old or the newer chambers, but not in the 375 Winchester Chamber.

C. 2.020" 375 Winchester brass that will fit in all the chambers.

3. Various chamber neck, bore and groove dimensions should be able to be accommodated by sizing down from a dimension large enough to fit the largest bore diameter (0.382?????).

4. A one-size-fits-all would be a bullet design dropping from the mold at a diameter of 0.382 with 3 crimp grooves spaced 0.055" apart that would theoretically allow the bullet to engage the rifling or lead in nearly every Brass/Chamber configuration.

5. It was also brought to my attention that, typically, the most accurate bullets from the twists used in the various lever guns have been in the 150-grain range, so the design was shortened to reflect that weight.

6. And last, but not least, the choice of either gas check or plain base should be considered.

The following designs are the result of the conclusions.

When more opinions and ideas are expressed, we can do it again.

Respectfully submitted,
Tom Myers
Precision Ballistics & Records

**45 2.1** · 01-03-2006, 10:51 PM

Good looking boolits and drawings. Myself, I like the PB the best. BTW, I have a Marlin and Win BB 375 Win. that take the modern 38-55 brass without a hitch. I've read of alot of others that do the same.

**Dutch4122** · 01-03-2006, 11:09 PM

Not sure if this helps or will just add fuel to the fire, but my early 80's Winchester '94BB in .375 Win has a throat measured at .418" with a jacketed slug seated backwards in a .375 Win case. Dan at Mtn. Molds has confirmed that he has had other customers report similar sized throats.

I'm sure mine would take the 38-55 brass without a hitch as well.

BTW, gas checked version for me, please.

**bdoyle** · 01-03-2006, 11:21 PM

Well, I'll have to go with #1-b clymer chamber on my 375 Win BB. It is an early top eject model. There is also a .200 throat before the rifling(sp??) starts. I have only used 2.08 win 38-55 brass in this rifle. The designs look good. Can't decide if a GC is needed or not.

Brian

**felix** · 01-03-2006, 11:34 PM

What is the projected maximum speed, and with what powder? That, if not using grex or PSB, will determine if a gas check is required or not, assuming no slop in the throat department. ... felix

**Buckshot** · 01-04-2006, 05:05 AM

..............I'm in for a mould, regardless of it's weight, so long as it drops at or may be sized to .382".

If I had my druthers, it'd have a GC.

BTW, when/if the times comes and we decide to start gathering checks I will post a sticky for that so it doesn't float all over the board, OR I can make this thread a sticky and we can just add the check count and info to it.

....................Buckshot

**grumble** · 01-04-2006, 12:32 PM

I'm in for a mold, too. Prefer GC, but will go along with the crowd.

**BorderBrewer** · 01-04-2006, 02:51 PM

Hi,
Please count me in for one of these. I also prefer gas checked if possible.
Thanks.

**moodyholler** · 01-04-2006, 04:41 PM

Count me in!!! TIA moodyholler

**chromecrow** · 01-04-2006, 05:38 PM

I too would be interested in this mould. I like PB but could go for GC if thats what the majority want.

**BlueSmoke** · 01-04-2006, 09:45 PM

I'll take a mould. PB or GC. I'm having a great time with a 240 gr plain base Lasercast .380 dia and 17gr of Accurate 5744 in my "new" USRAC 38-55 hunter.

**Nrut** · 01-05-2006, 02:29 AM

Originally Posted by 45 2.1

Good looking boolits and drawings. Myself, I like the PB the best. BTW, I have a Marlin and Win BB 375 Win. that take the modern 38-55 brass without a hitch. I've read of alot of others that do the same.

I can't speak to the Marlin .375 but I own a Win.BB.375 and it will easily digest 38-55 brass....I tried it after I read one of Paco Kelly's articles on using 38-55 brass in his Win.BB.375...he uses .38-55 brass,Speer 235gr. Jacketed (with nose flattened) and 42.5 grs. of RL-7 for just under 2400 FPS and 3000+ of energy in a 20" barrel......He likes 38-55 brass because it has a 3 to 4 gr. case cap. advantage over the .375 BB brass (besides being shorter .375BB brass is thicker)...I have not tried Paco's load and probably won't as I'm not into self abuse...but the point is that it may not be neccsary to put and extra crimping groove on to accommodate .375 BB brass...
I recently received a mold from Dan @ Mt Molds that is basicly like the above design but with no crimp groove(I use a Lee Factory Crimp die just to take out the case flare)...
spec. on Dan's sofware are as follows
260gr./ gc.
.383"
.170" front band
.525" nose lenght
62% (.237") meplat
.8 GtoB with two grooves
I bought this mold mainly for my Uberti 1885 Low Wall(.380" groove), MarlinCB, and couple of old Winchester 94's in 38-55.......the Marlin has .381+ groove and will only chamber a .379 bulllet in a unmodified case.......this last weekend I modified my neck turner to turn the necks on the brass the full lenght of the bullet and now the Marlin will chamber the the .382" sized bullet....OH Happy Day!!!...My only concern is that I may not have enough lube for the 30" barrel on the Uberti as with plain based Lee .380-.381 bullets I was getting leading in the last 4" or 5"of the barrel...the gas check and sligthly fatter bullet may cure this.....can't wait for break-up and spring weather to try those bullets out....
Yes Tom I'll take a 6 banger if it has a gas check and a min. dia. of .382".....cheers mic

**Frank46** · 01-05-2006, 02:45 AM

Out of curiosity, has anyone measured the throat diameter of their 38-55's or 375 wins?. I have a win bb in 375 but as of yet have not started casting for it. I had heard that (either on shooters.com or here) that the win's had large throats. Sounds like I need to check mine out also. This will be my first group buy so would like gas checked bullet and the .382
diameter. Maybe Lee will get this one right. Tom, thanks for the design. Frank

**bdoyle** · 01-05-2006, 11:33 AM

Frank,
I have a top eject Win94 375BB. The throat dia is .380 with a bore of .377. This is likely the first year of production, don't know what they did after that.

Brian

**Tom Myers** · 01-05-2006, 12:29 PM

We are still waiting for someone to step forward and offer to Honcho this group buy. It appears that some are assuming that I was going to do this one. I should have stated more clearly in the previous post that, because of temporarily unstable health , I can only help with the design and sketches needed to design the mold according to the wishes of those interested in the group buy. So, could someone please offer to do this one, this particular design is starting to look too good to pass up.

NRNut brought up the point that a third crimping groove would not be needed as the regular 38-55 brass could be used in the 375 Winchester chambers. I am wondering about the guy that maybe has a 375 Winchester and a couple hundred pieces of 375 Win brass that may want to get in on the group buy. If there is nobody in that situation, then there is absolutely no reason for the third crimp groove and it could be eliminated before the final configuration. So the third crimping groove option should be addressed when expressing an interest in the group buy.

Since there are those that use the 375 brass and blown out 30-30 cases, the need for the third groove is apparent, so the 3 crimp groove should stay.

**45 2.1** · 01-05-2006, 12:44 PM

Please leave the third crimping groove in. A number of us use 375 brass and blownout 30-30 brass in both calibers. The third groove is necessary.

**BorderBrewer** · 01-05-2006, 01:15 PM

Hi Tom,
Please leave the third groove. I will use this in my 375. Thanks.

**JD2** · 01-05-2006, 04:25 PM

I'd go for one. Either GC or PB is fine with me.

**lar45** · 01-05-2006, 05:23 PM

I like it and will definatly buy one. I think a Gas Check version will work better for me. What of the BPCR sillouette(sp) guys that will need a plain base? Does anyone use the 38-55 in that game? or is more bullet mass needed?
I have the Win BB. I haven't measured anything in it and have only played a little with the Lee 250.

**Dutch4122** · 01-05-2006, 08:52 PM

I'm also heavily invested in .375 Winchester brass and would appreciate it if the 3rd crimp groove were left in.

I'll tell ya, this one almost begs for 2 separate runs; one with gas check and one with plain base.

BP	Bronze Point	IMR	Improved Military Rifle	PTD	Pointed
BR	Bench Rest	M	Magnum	RN	Round Nose
BT	Boat Tail	PL	Power-Lokt	SP	Soft Point
C	Compressed Charge	PR	Primer	SPCL	Soft Point "Core-Lokt"
HP	Hollow Point	PSPCL	Pointed Soft Point "Core Lokt"	C.O.L.	Cartridge Overall Length
PSP	Pointed Soft Point	Spz	Spitzer Point	SBT	Spitzer Boat Tail
LRN	Lead Round Nose	LWC	Lead Wad Cutter	LSWC	Lead Semi Wad Cutter
GC	Gas Check

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