200 gr. Boolits in the 32Spl??

[Marlin Junky]

What's the heaviest (longest) boolit anyone has tried in the .32Spl? I looked for months for a fast twist .32Spl under the impression (because of what I was told during a phone call to Marlin) that Marlin made some .32's with 12" twists. At this point I'm pretty sure the guy at Marlin who told me this was full of IT. Since then, I found info in Brophy's book indicating the rate of twist for ALL Marlin .32Spl's was 16".

So... I fiddled a bit with Mountain Molds' interface and came up with a .321", 200 grain GC'd boolit weighing 200 grains +/- (WW & 2% Sn) that has an overall length of 1.003" and about 61% bearing surface. Then I did a quick calculation using Greeny's formula and came up with a 15.4" rate of twist... pretty close to the common 16" twist found in most, if not all, .32Spl's. Now I'm curious enough about the 16" twist to start looking for a Ballard rifled Marlin in .32Spl to shoot custom 200 grain boolits through! Am I wasting my time??

MJ

[wmitty]

I'm interested in this also; I'd considered rebarrelling a M336 .30-30 with the .32 WS barrel which is available from Numrich but decided the 16" twist just wasn't going to allow a bullet much heavier than 180 grains to be stabilized. I couldn't see any advantage over the .30-30 unless a fast twist barrel was obtained. I'd be very interested in finding what the upper weight limit is with the 16" twist rate.

[felix]

I would limit the length to equal the RCBS boolit which has shown perfection in the Winnies with 16 twist. ... felix

[Scotty]

Scotty,:coffee:

[BruceB]

" At this point I'm pretty sure the guy at Marlin who told me this was full of IT. Since then, I found info in Brophy's book indicating the rate of twist for ALL Marlin .32Spl's was 16". "

MJ, sir;

Brophy or not, my Marlin .32 Special of 1947 manufacture (Model 36, not 336) has a TEN-inch twist, and no doubt about it. Ol' Gringo, who used to hang out here but has disappeared, also had a Marlin of similar vintage with the same twist rate as mine. He personally contacted Marlin and was told that they DID in fact make rifles with the faster twist in that time period.

I'd haunt the used-gun racks in hopes of finding such a late-'40s Marlin .32 if the fast twist appeals to you. The Model 36 rifles were very nicely made, and are a bit different from what we normally see....always a nice thing in my book.

Sundog put it very well, though, when he stated that what Ol' Gringo and I have are just "fat .30-30s". I use the RCBS 32-170 in mine with good success, but haven't come anywhere near exhausting the possibilities with that bullet.

[Bret4207]

If you can find a barrel that will handle the 200 grainer, then you should be able to at least match 303 Savage velocity, and that is a deer killing load IMHO. 190 gr FN (or Silvertip if you are one of the un-clean types) at 1900-2000+ fps is a dependable load. Anecdotal evidence from the early part of the 1900's when it was in it's heyday shows the 303 to be considered a much more reliable killer than the 30-30 due to the heavier bullet. The 32 Special should do the same thing. Plus, it's a 32 and that gives it "cool" factor, at least to a 32 fan like me.

[26Charlie]

That's the designation of a mountain mould he did up for me, in brass. It has an OAL of .915" and weighs 191 out of the mould, 195 with GC ready to go. I asked for a 70% meplat as I recall, which he had a little trouble with, something about the boring bar not reaching quite right, and so the nose was a little fatter than he anticipated. The design has two grease grooves and a crimping groove, fills the neck of the case, and is short enough to function and to stabilize OK. The slightly fat nose gives a faint resistance to chambering and also leaves rifling crease marks on the bullets, which might be a problem with linotype but is no problem at all with wheel weights or range scrap.

I wanted the 190 weight because of those stories mentioned above about the .303 Savage.

[Marlin Junky]

BruceB,

According to Brophy, all Ballard rifled .32Spl's made by Marlin were .318" in the grooves which is less than .010" wider than my Ballard rifled 30-30's. Not a big difference and I can see why they are called "fat 30-30's". I'm going to keep an eye peeled for all pre-336 .32Spl's but what I'm really after is a 1st Variation M1936 (long tang).

Regarding performance: I'm getting over 2100 fps from a 1950 issue 336A in 30-30 using a case full of H414 behind RCBS-30-180FN (195 grains checked) with very satisfying accuracy. I don't know how much pressure I'm generating, but it may be pushing the envelope for a pre-336 gun. If my only consideration was performance, I'd probably just have an E, F or G 30-30 bored out to .323 (8mm). This combination would likely reach 2200 fps with a 200 grain boolit from a 22" barrel and with the proper boolit, be sufficient for hunting everything in N. America from mice to moose (sans the big bears).

MJ

P.S. Could it be possible that Marlin bought German barrels for their .32's right after WWII? Could that explain the run of 10" twist .32's?

[felix]

That has been my guess all along! Winchester set the standard, and Marlin must have had an economic reason for not following it. ... felix

[Marlin Junky]

Felix,

I believe the standard for rate of twist in .32 caliber was set by Ballard with the 32-40 in 1884. Both Marlin and Winchester followed suit in 1886.

MJ

[6pt-sika]

BruceB,

According to Brophy, all Ballard rifled .32Spl's made by Marlin were .318" in the grooves which is less than .010" wider than my Ballard rifled 30-30's. Not a big difference and I can see why they are called "fat 30-30's". I'm going to keep an eye peeled for all pre-336 .32Spl's but what I'm really after is a 1st Variation M1936 (long tang).

Regarding performance: I'm getting over 2100 fps from a 1950 issue 336A in 30-30 using a case full of H414 behind RCBS-30-180FN (195 grains checked) with very satisfying accuracy. I don't know how much pressure I'm generating, but it may be pushing the envelope for a pre-336 gun. If my only consideration was performance, I'd probably just have an E, F or G 30-30 bored out to .323 (8mm). This combination would likely reach 2200 fps with a 200 grain boolit from a 22" barrel and with the proper boolit, be sufficient for hunting everything in N. America from mice to moose (sans the big bears).

MJ

P.S. Could it be possible that Marlin bought German barrels for their .32's right after WWII? Could that explain the run of 10" twist .32's?


In all my Marlin 32 Speciels and my Marlin 32-40 I use bullets that were sized in a .323" die . And they shoot very well , granted WW's are not a very hard alloy.

[BruceB]

If Marlin was using left-over barrels from some other production, I don't know what they'd be from. These .318/.319" barrels would be very much undersize for any 7.92 cartridge except the ancient 7.92 J, of 1888 vintage.

I think it might be POSSIBLE (not "likely") that Marlin used on-hand machinery from wartime production to rifle the barrels. The twist rate is more important than the diameter, in my opinion. The reason the .32 Special has such a good reputation among casters is the 1-in-16" twist, as opposed to the 1-in-10" of the .30-30 and other well-known .30 caliber rifle rounds. I thought I was buying a "real" .32 Special at the time I obtained the M36, but in fact it was a "fat .30-30", just as Sundog named it. I'm sizing RCBS 32-170s at .319" in a Stillwell custom die.

I still like the rifle, though, and it's shooting pretty well with relatively-little load development to date.

[Marlin Junky]

BruceB,

You're probably right about the .32 barrels.

But, a 1 in 10" Ballard rifled 30-30 can be a real tack driver with long gas checked boolits.

I'm just going to have to acquire a .32Spl with 16", 14" and 12" twists to see for myself, I guess. Hey, I've got an extra 336 that doesn't see much use! Perhaps I'll put a new barrel on it... a .32Spl barrel with a gain twist :-D. I wonder how much that'll cost and who could do it. Any input, anyone?

MJ

[MTWeatherman]

I wouldn't rule out stablizing that 200 gr. bullet in a 16" twist .32 just yet..at least for the shorter ranges.

Its the length of the bullet...not the weight that determines the necessary twist. However, another consideration not frequently considered is bulllet density. For two bullets of equal weight and essentially equal design, you can get by with slightly less twist using cast (assuming equal velocity) than jacketed. Conversely, with equal length and design, you can also stabilize a somewhat heavier bullet using cast because the cast bullet is heavier. Replacing the gilding metal with lead at the outside of the bullet provides more centrifugal force to the rotating bullet There is slightly more of a a "gyroscopic" or stabilizing effect carried by the cast or lead bullet than a jacketed one.

Scotty's chart shows a .323 bullet out of a 16" twist having a maximum weight of 189 grs. for stabilization. Now, the .32 Special is a .321 and would result in slightly less possible allowable weight for stabilization under the same conditions. However, that .323 is an 8mm and likely is at least a roundnose if not a spitzer design....therefore longer than an equivalent .32 Special bullet of equal weight would be with its flat nose. I strongly suspect that with a decent meplat, you could create a cast flat nosed bullet of 200 gr. with the same length as the jacketed 8mm bullet in Scotty's chart. The .32 Special would then stabilize it assuming it has enought velocity to do it.

Missing from the chart is the velocity those bullets were driven at...that 8mm could have been driven pretty fast in the test. It is possible that the .32 couldn't get the velocity required for more than short range stabilization with the 200 gr. However, I use that RCBS bullet with a 3 WW to 1 Lino ratio and it runs about 179 gr...straight WW puts it a bit over 180. That bullet out of my .32 is stabilized very well to over 175 yds and a pure WW would have the edge on it due to the weight advantage. Seems to me, with proper design, the odds would favor being able to design a 200 gr. cast bullet short enough to be stabilized by the .32 Special to at least 100 yds.

Only way to find out would be to try it...but its pretty hard to beat that RCBS bullet for performance.

On another note, it seems that not only Marlin but ammuntion manufacturers may have used war surplus equipment in producing not only barrels but ammuntion for the .32 Special. Marlin essentially used 8mm barrels in the 40s as already pointed out...German machinery? However, Mic McPherson pulled some .32 Special ammo made early in the 1900s to discover .318 bullets in them. He felt that the use of undersized bullets at the time, at least by some manufacturers, went a long way toward explaining the .32s reputation as having poor accuracy with worn barrels. Bullets .318? Thats the old pre '98 Mauser bullet. More war surplus? Maybe Marlin came out with the .318 barrel to compensate.