231 for 200gr SWC vs 231 for 230gr RN

[Roland Thunder]

I have been using 45acp 200gr SWC's for a long time in my 1911 but they don't feed so well in my Sig 320 so I bought some 230gr RN's. I loaded some 230gr RN's with 4.8 grains of 231. My 200gr SWC's are also loaded with 4.8 grains of 231. When I went to shoot my Sig 320 today, the 200gr SWC's loaded with 4.8gr of 231 were a milder load than 4.8gr of 230gr RN (same OAL). I was a little surprised. I would have expected 200gr SWC's to be a hotter load than 230gr using the same amount of powder and the same OAL since the SWC's are lighter.

How many grains of 231 would you expect to use in 230gr RN's to have similar recoil to 4.8gr 231 in 200gr SWC's, OAL being about the same

[Nick_C_S]

No doubt your 230 grain bullets, being seated to the same OAL will leave much less internal case volume. The 230 bullet - being longer - will seat much deeper in the case - and that is a huge contributing factor to its performance.

The same amount of propellant put into a smaller space, along with the requirement to push a heavier bullet, no doubt resulted in much more peak pressure.

You have created a condition (ammunition) far more apples-n-oranges than apples-n-apples.

Internal case volume is an important concept to understand when loading ammunition. It plays a major role in the way the propellant behaves. Variables abound, but overall, the less case volume for a given amount of propellant, the faster the propellant's burn rate. The result obviously, is a higher peak pressure. You experienced this first hand. I ran the data (what I had, anyway) though QuickLoad and your 200 LSWC's yielded 12.2Kpsi; while your 230's ran at 15.6Kpsi. Actually, I expected the difference to be greater; but the point remains.

I wish I could directly answer your question, but I can't. "Something less than 4.8 grains" would be the best I can do.

Coincidentally, I just walked in from the loading bench - having loaded 100 rounds of 200gn LSWC, with 5.0 grains of W231 (it was labeled as HP-38 actually - same stuff). But I don't load a 230gn lead RN. The 200 is the only lead bullet I load for 45 ACP (and they're awesome, I might add). Everything else is plated or jacketed, and generally, a little hotter.

[44 AMP]

No doubt your 230 grain bullets, being seated to the same OAL will leave much less internal case volume.

actually, I have some doubts. You are entirely right about how changes in powder space affect pressure, but in this case, with the information provided, I cannot say with certainty if the OP is actually seating the 230gr bullets significantly deeper.

This is because he does not identify the bullets he is using, other than by weight & style. There are styles of 200gr swc slugs that are the same length as a 230rn, and would seat to the same depth.

When I went to shoot my Sig 320 today, the 200gr SWC's loaded with 4.8gr of 231 were a milder load than 4.8gr of 230gr RN (same OAL). I was a little surprised. I would have expected 200gr SWC's to be a hotter load than 230gr using the same amount of powder and the same OAL since the SWC's are lighter.

This makes me wonder, how are you judging "milder"?? by recoil?? muzzle blast? Chronographed velocities???

A heavier bullet, even at a lower speed can have more felt recoil, and seem like a "hotter" load.

4.8gr W231 is a pretty light load, and below the starting load in some of my old books....

[USSR]

I have been using 45acp 200gr SWC's for a long time in my 1911 but they don't feed so well in my Sig 320 so I bought some 230gr RN's. I loaded some 230gr RN's with 4.8 grains of 231. My 200gr SWC's are also loaded with 4.8 grains of 231. When I went to shoot my Sig 320 today, the 200gr SWC's loaded with 4.8gr of 231 were a milder load than 4.8gr of 230gr RN (same OAL). I was a little surprised. I would have expected 200gr SWC's to be a hotter load than 230gr using the same amount of powder and the same OAL since the SWC's are lighter.

How many grains of 231 would you expect to use in 230gr RN's to have similar recoil to 4.8gr 231 in 200gr SWC's, OAL being about the same

According to Winchester's load data, your 200gr lead SWC with 4.8gr of W231 is doing 800fps with 14.9k psi of pressure. This is listed as a starting load. The starting load for your 230gr lead RN bullet is listed as 4.5gr of W231 with a velocity of 765fps and pressure of 15.5k psi. Hope this is of some help.

Don

[T. O'Heir]

"...to have similar recoil..." It won't be the same, but the felt recoil of any 230 is negligible.
A 200 with 231 is actually a tick faster than like loads with a 230. Applies to jacketed or cast too.
4.8 grains of 231 is mid range load for any 200 or 230 grain bullet. You should work up the 230 grain load, but you probably won't notice any difference between 'em.

[armednfree]

Bullseye recipe used for decades. 5.1 grains 231 and a 230 grain bullet. Jacketed or lead, makes no difference. I have never seen that load not shoot well.

[reddog81]

To add to the confusion it all depends on the exact bullets being used. The original H&G 68 200 grain SWC was developed to have the same bearing surface area and amount of bullet in the case as a 230 grain RN bullet. Of course today there are a wide variety of 200 grain SWC's with slight variations on the nose and driving bands which of course effects the amount of bullet in the case and therefore the pressure.

You'll have to experiment with the loads to find ones that replicate each other in your guns.

[armednfree]

I would have expected 200gr SWC's to be a hotter load than 230gr using the same amount of powder and the same OAL since the SWC's are lighter.

I would not expect that at all. The pressure generated by the 220 and the 230 are different. We are looking at a pressure difference of 5000 +/- CUP. Your load of 4.8 behind a 200 grain is extremely mild. You have to remember that with a fast burning powder 1 grain makes a huge difference in pressure in a pistol case.