Why the discrepancy in Lyman's for .32 cal?

[Javelin Dan]

Hi folks! I'm currently bidding on an H & R .32 mag I'm hoping to win. Was looking in my Lyman's 49th at some loading info, and discovered what looks to my newbie eyes to be a discrepancy. Looking at .32 long specs (already have some of this brass), a max load of 3 grains of bullseye with a 75 grain bullet produces 958 fps velocity. Turning the page to .32 H & R magnum shows a starting load of 3 grains of Bullseye with a 75 grain bullet producing 1064 fps.

Now I'm new to all this, but given that the magnum case is longer than the "long", wouldn't the distance between the powder charge and the bullet be greater and therefore produce less pressure and less velocity not more? What gives?

[dilly]

Real world numbers do not always follow theory. Perhaps it was a different revolver used to test the two guns. Were the barrel lengths the same?

Perhaps it was the same revolver, but the excess cylinder two barrel jump cause the decrease in pressure for the smaller cartridge.

Perhaps the different guns have different cylinder gaps.

I don't think there's quite enough information to really say.

[Gus Youmans]

Dan,

Notice that the data for the .32 S&W Long was obtained from a 4" revolver and the .32 H&R Magnum data was obtained from a 5" universal receiver. In addition to the longer barrel, I think universal receivers are not vented and don't lose velocity through a cylinder gap.

Gus Youmans

[olafhardt]

I have loaded 32SWL for several years. I started with a Lyman press, Lee dies, and a Lyman Manual. I started off with the minimum load and got godawful muzzle blast, leading and recoil. Now I love 32 handguns and read all the reloading data I can find on the 32's. The principle thing I have found is that it's very erratic and confusing. Here is my current thought for 32 SWL. Start with 2 grains of fast powder and work up with 100 grain max booolits. An 80 -100 grain boolit at 800 ft/sec will do what a 32 is good for. If you want more buy a 38.

[Harter66]

I can't remember if it is in the Speer book or Lyman , why balistians get grey . It includes a table with about 25 revolvers and 1 load (I think, it's been a long time ). It shows that even identical pistols will shoot at different velocities and that occasionally a 4" bbl will out run a 6" . It also shows the huge loss for the change from 6 to 4 to 3 to 2 inch bbls .

The "ported" aka cylinder gap bbl in the Universal receiver is closer to actual numbers .

[rintinglen]

I can't remember if it is in the Speer book or Lyman , why balistians get grey . It includes a table with about 25 revolvers and 1 load (I think, it's been a long time ). It shows that even identical pistols will shoot at different velocities and that occasionally a 4" bbl will out run a 6" . It also shows the huge loss for the change from 6 to 4 to 3 to 2 inch bbls .

The "ported" aka cylinder gap bbl in the Universal receiver is closer to actual numbers .

That was originally in Speer Number 9, IIRC. It decisively demonstrates the rule that every gun has its own characteristics and preferences and why ALL data is "real and actual only for one time and place."

It is re printed in their Reloading Manual 14. It is a very enlightening read and makes one appreciate the availability of inexpensive chronographs.

[Outpost75]

In a cartridge similar to the .38 Special or .32 H&R Magnum, each 0.001" change in cylinder gap from Mean Assembly Tolerance results in approximately a 10 fps Delta-V in velocity, being higher for a tighter gap, and lower for a looser gap. Depending upon the ammunition used, it is entirely possible for a 2" revolver having a tight cylinder gap at minimum assembly tolerance, such as 0.002-0.003" to produce equal or higher velocities than a 4" barrel at Mean tolerance, typically 0.005-0.006" or a 6" gun at maximum tolerance, generally 0.008". This is based on experience firing standard pressure and +P .38 Special service loads in large samples of production guns. Firing .38 Special ammo in the correct .38 Special chamber, rather than in a longer .357 chamber, which may result in lower chamber pressure firing in the .357, due to gas leakage around the bullet, may also lower velocity in .357 chambers vs. .38 Special with same ammo, cylinder gap and barrel length.

I would expect similar performance firing the .32 H&R Magnum and .327 Federal.

[Javelin Dan]

Hey thanks guys - ALWAYS a pleasure and an education to interact with you! Ya know, I did look at the barrel length in the .32 long data, but skimmed right by it in the magnum specs. Yep, that sure would explain things. My bad. The sad news is, I lost the auction and with winter approaching (a time of "underemployment" for me), I will have to put off my dreams of a new .32 mag till spring. Oh well, I can buy it, load for it and shoot it in the virtual reality of my brain. We hot-rodders call it "bench racing".

For the record, lest anyone fret about my intentions, I really wasn't going to start out with 3 gr. of Bullseye. I only used that measure because it showed up in the data for both chamberings. I actually figured I would start with 2 gr. of Bullseye with a 76 gr. cast RN-FP bullet in a .32 long shell as I have all ingredients in stock. I would eventually look to move up to something like a 100 gr. WC and about 2.5 gr. of powder. I figure my H & R 732 should digest that without too much heartburn, and as olafardt suggested, adjust (up or down) according to performance. My intention is to eventually score the more versatile .32 magnum (the gun I probably should have bought in the first place), and maybe sell the 732 as I wouldn't need both. I may never end up loading anything other than the long shells for it anyway. All this leads to one more question: does anyone know if I can load for the .32 mag with the .32 ACP dies (Lee's) I have now? I know I can load for .32 long with these as I've seen it documented by others who have done it here and elsewhere. The length of the case vs. the working distance of the dies is the only unknown for me. Anyone know?

[Outpost75]

The Lee .32 ACP dies are not perfect for your proposed application, but they will work. The main problem I see is that they may size brass excessively and if they taper crimp, rather than roll crimp, it may not be adequate to prevent inertial dislodgement of bullets in heavier revolver loads. But you won't know until you try, and I would encourage you to do so before spending money on another set of dies which you may not need. Sometimes you get lucky.

[MT Gianni]

Lee 32 long dies will load 32 H&R and 327 Fed. $20 well spent.