PPC .38Spl Barrel Twist Rate? 1:12 or 1:14?

SPDGG · May 12, 2010

Hello,

Been searching into twist rates for PPC revolvers shooting light load .38Spl 148grn WC. I understand the faster twist rate is needed for the long HBWC bullets used for these revolvers. But, I would like to know which preforms better at distance mechanically, minus shooter, or is this just personal preference.

Are there any rules in PPC shooters use for each twist rate in regard to powder charge, bullet weight/type or muzzle velocity?

Which of the two twist rates would you recommend, have used, & why?
* 1:12
* 1:14

Seems to be a split between the two twist rates from what I have read and what I can make from barrel manuf. offerings. Any information would be greatly appreciated.

Thanks & Have a great one

JKeefer · May 12, 2010

SPDGG said:
Hello,

Been searching into twist rates for PPC revolvers shooting light load .38Spl 148grn WC. I understand the faster twist rate is needed for the long HBWC bullets used for these revolvers. But, I would like to know which preforms better at distance mechanically, minus shooter, or is this just personal preference.

Are there any rules in PPC shooters use for each twist rate in regard to powder charge, bullet weight/type or muzzle velocity?

Which of the two twist rates would you recommend, have used, & why?
* 1:12
* 1:14

Seems to be a split between the two twist rates from what I have read and what I can make from barrel manuf. offerings. Any information would be greatly appreciated.

Thanks & Have a great one

Hello Sir;
Your question is one that I pursued extensively for many years.
In brief, the best ever groups I achieved were with a Kreiger 1-12 twist barrel. I built four guns from that blank, and all four would shoot well under an inch at 50 yards. I have also been able to get very close to that with Shilen 1-12 and 1-14. 1-10 twist was a very popular twist in the early days. Good ammo is a must.. Remington bullets are hard to beat...WST powder by far produced the best groups, then.. Things may be different now.. I don't do much PPC revolver work or testing anymore..mostly autos for PPC ...revolvers and autos for bullseye. In reality, I think precision machining has more to do with it than slight changes in twist rate. If you can find a smith who puts the same precision into the work that one would put into a match winning benchrest rifle, you'll have a winning gun. Freebore/Taylor throating is a big plus. Rigid cylinder support and alignment, all aggregate to the performance of the gun..

Good luck

Jerry

SPDGG · May 16, 2010

Thank you very much for the detailed feedback/info from your experiences Jerry, Really appreciate it.

Just not sure which route to go, 1:12 or 1:14?

K38 · May 16, 2010

I have always wanted a gun with a Kreiger barrel. They are legendary in the Palma world.

Espen · May 17, 2010

SPDGG said:
Just not sure which route to go, 1:12 or 1:14?

It' doesn't really matter. The twist rate has only one mission in life, to stabilize the bullet. To often you will come across people that think the twist rate can do some magic stuff. The importance of the twist rate can NOT be transfered directly from a bench rest rifle to a revolver.
Anything from 1:10 to 1:20 will stabilize a 148 grain HBWC out to 50 yards. And will do so inside a speed range from as low as you never will go, and upwards way beyond stupid.

The magic here is just what JKeefer is guiding you towards, a good quality barrel. Kreiger, Shilen, Douglas, Lothar Walther all good stuff.
I'm using a 1:17,7 polygon barrel from Lothar Walther.

Jebus35745 · May 17, 2010

I have a project gun I'm going to build and someone gave me a slab side 1-16" bbl, mfgr unknown. It was a left over from a retired gunsmith of known workmanship. Good to know a 1-16" twist will do what I want seeing that Smith used 1-18". Frank, good luck with your project. Larry

SPDGG · May 18, 2010

Espen said:
The importance of the twist rate can NOT be transfered directly from a bench rest rifle to a revolver.

Well I guess you can see what was spinning my head. I am more familiar with long gun twist rates and bullet length/weight. Pistol info. not so much. Thanks for the insight.

Espen said:
The magic here is just what JKeefer is guiding you towards, a good quality barrel. Kreiger, Shilen, Douglas, Lothar Walther all good stuff. I'm using a 1:17,7 polygon barrel from Lothar Walther.

+1 Agree, Nothing beats a Quality Match Barrel for accuracy. Plan on Douglas or Lothar Walther.

Jebus35745 said:
Frank, good luck with your project. Larry

Thanks Larry, Good luck on yours as well.

Espen · May 18, 2010

SPDGG said:
Well I guess you can see what was spinning my head.

You are not alone

A bunch of us had this discussion some time ago. We had all listened to the myths and rumors over the years. After finding seven different formulas for calculating the best twist, we at least agreed on the fact that nobody else agreed on it...
Then we handed the problem over to people that know physics, mathematics and nothing about guns. So the didn't know the myths

The first thing I learned was that there is no good or bad stabilizing, it is simply yes or no.
I don't recall all the numbers they came up with, but for a 6" PPC revolver the numbers just made us laugh. I think it was something like this, for barrels from 1:10 to 1:20 with most common .357 bullets from 120 to 160 grains you need to be under 250 f/sec or over 2900 f/sec.
I'm not worried...

I have a 15-4 with a 1:12 Douglas barrel, and a 66-2 with the polygon Lothar Walter barrel. Both are capable of a lot more accuracy than "the pilot".
I never shoot any lead HBWC's in the LW barrel, so i have no idea how that works. I only use 125 grain copper and plastic coated Haendler & Natermann bullets.

Good luck on you project. I'll will try to get some pictures of our latest projects. Here is the first one that is almost finished, it's missing the under lug and a new thumb release.
I know, I know.. it's built on a Taurus. (I was actually surprised over the quality and how easy it was to build on, but don't tell any one on this forum)

Espen · May 23, 2010

The 66

If i was a good at thaking pictures, I would be on a different forum

BE Mike · Apr 17, 2018

Jerry Keefer (RIP) also said that traditionally, custom PPC revolvers used a 1:10 barrel twist and most of them shot under an inch at 50 yards with no bullet tipping. He didn't think that the S&W model 52 barrel twist rate of 1:18 3/4 was optimum for 50 yard shooting. That is probably the reason that Clark is making their after market S&W model 52 barrels with a faster twist rate. They also have a lot of experience with building PPC revolvers.

Protocall_Design · Apr 17, 2018

I've built a lot of PPC guns from 1980 till now. I have always used 1:10 .357 bore Douglas barrels with extremely good results. My current couple of guns have a close metric equivalent of 1:10 Walther barrels that are .355 bore. Walther didn't have any .357 blanks and lists the .355 for .38/.357.

The Open class Bianchi with Walther barrel shoots 3/8" groups at 25 yd. and around 1" at 50 yd. out of a Ransom rest. This is with 125 gr. JHP at 1050 fps.

I think 1:12 is about the ideal twist rate for target loads, but couldn't find any 1:12 blanks, so used 1:10. From my experience, 1:18-3/4 S&W twist is too slow for target loads at 50 yd. The 1:10 to 1:14 barrels have always shot a lot tighter groups in actual testing than S&W factory barrels at 50 yd. with slow target loads.

I wish S&W would go to 1:12 across the board for all their revolvers.

PPC .38Spl Barrel Twist Rate? 1:12 or 1:14?

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