WA1500 Twist Rate of Barrels

Joined: December 29th, 2016, 8:08 am

December 29th, 2016, 8:18 am #1

I am just asking around as to why gun builders these days recommend a 1:24 twist barrel for both Revolver and Pistol ? instead of the 1 in 16 twist.
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Joined: January 22nd, 2012, 7:12 pm

December 30th, 2016, 1:55 am #2

would you mind stating which gunsmiths???

If your speaking .38 specials, I think it's been pretty clear that 1:10-1:14 covers the requirement pretty well...

Jim C
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Joined: December 29th, 2016, 8:08 am

December 30th, 2016, 2:01 am #3

Gunsmiths here in Australia like Max Wray and Ray Pulver recommend 1:24 for WA1500 for some reason and I want to understand why ?
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Joined: January 22nd, 2012, 7:12 pm

December 30th, 2016, 4:07 am #4

It's possibly the use of ultra light (100 gr) bullets.
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Joined: December 29th, 2016, 8:08 am

December 30th, 2016, 5:01 am #5

I have an STI with a 1:24 Pulver bull barrel and it seems to only really like the 100gr SWC. I guess I have never tried the 115 FMJ as my range does not permit Jacketed bullets, so I haven't tried everything yet. It's interesting because they don't stabilize till just over 1050 FPS and from a rest hold about a 1.5" group @ 50 Yards. I did manage to get some 125gr Conicals to group under 1" @ 50 yards but they didn't even come close to cycling the gun.
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Joined: August 21st, 2013, 3:31 pm

December 30th, 2016, 5:02 pm #6

Interesting, I have a STI Targetmaster with 6" bbl. They are 1:16 and when I first got it couldn't get it to shoot better than 6"-7" at the 50 out of a Ransom. Sent it back to STI twice and they replaced slide, then finally bbl and I am getting 2"-3" at 50 now with 115 grain JHP Wincheser boolits. They wont tell me what bbl they are putting in them, but whatever it is quality something to be desired(at least one I got)Now I know why the person I bought it from sold it. Shame, it is a solid well built pistol, but lacks ability in what it is supposed to do. Must say their customer service was top notch. Everyone I have since talked to that had one has changed the bbls in them. Several said the lower end Trojan shot better than the Targetmaster.
As heavy as the slide is have to load them up around the 1200fps to get the thing to function, but recoil still mild with all the weight. If I keep it, might have to invest in another bbl, but hate doing this to a gun that is supposed to have performed good to begin with. I know my shooting prowess has depreciated, but out of a machine rest, as someone stated previously, takes the stoopid factor out of the equation,it should perform.
In the past we have tried some 90 XTP's grain JHP boolits out of the PPC9 and Targetmaster and they were all over the place.Maybe need to try some of the 100 grain lead SWC in the Targetmaster.
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Joined: November 13th, 2016, 7:50 pm

December 31st, 2016, 3:59 am #7

It appears to me that a much slower barrel twist rate is not an advantage.

First is obtaining very light FWC light bullets. Most of the big commercial casters make 148 grain lead bullets for target...and they work very well. Plus, try & finds swagged lead 100 grain bullets.

Two. A much slower twist rate as suggested goes against the grain (pun intended!) of what most PPC revolver shooters know. And have proven.
It is much easier to use a faster twist rate and a lower velocity for 148 grain FWC's to achieve accuracy, than push a much lighter bullet of whatever construction at a higher velocity. It appears that a faster moving light FWC has little time to really stabilize in flight. Plus, this much lighter bullet will have a significantly smaller driving band to create accuracy with such s slow spin. It appears that this concept is entirely anathema to accuracy.

PPC is all about timed accuracy, & has no power factor. PPC revolver shooters have solved the accurate load problem. It is the human operator that determines winners.....

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Joined: December 29th, 2016, 8:08 am

December 31st, 2016, 6:49 am #8

Interesting, I have a STI Targetmaster with 6" bbl. They are 1:16 and when I first got it couldn't get it to shoot better than 6"-7" at the 50 out of a Ransom. Sent it back to STI twice and they replaced slide, then finally bbl and I am getting 2"-3" at 50 now with 115 grain JHP Wincheser boolits. They wont tell me what bbl they are putting in them, but whatever it is quality something to be desired(at least one I got)Now I know why the person I bought it from sold it. Shame, it is a solid well built pistol, but lacks ability in what it is supposed to do. Must say their customer service was top notch. Everyone I have since talked to that had one has changed the bbls in them. Several said the lower end Trojan shot better than the Targetmaster.
As heavy as the slide is have to load them up around the 1200fps to get the thing to function, but recoil still mild with all the weight. If I keep it, might have to invest in another bbl, but hate doing this to a gun that is supposed to have performed good to begin with. I know my shooting prowess has depreciated, but out of a machine rest, as someone stated previously, takes the stoopid factor out of the equation,it should perform.
In the past we have tried some 90 XTP's grain JHP boolits out of the PPC9 and Targetmaster and they were all over the place.Maybe need to try some of the 100 grain lead SWC in the Targetmaster.
JB
I had no success with anything but the 100gr SWC in my STI, its a 1:24 twist Pulver BBL with a "Nose Cone" bolted onto the front of the barrel and there is no bushing so the end of the slide face locks up against the end of the block on the barrel as you can see below. Very tight lock up and a noticeable clunk when the slide batters forward which takes some getting used to but it will go sub 1.5' off a sand bag.




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Joined: September 8th, 2014, 8:24 am

December 31st, 2016, 8:13 pm #9

Interesting discussion once again, it seems that there are as many different reasons to try as many different twist rates as the dollars would allow. Is there an optimum twist rate? I had a copy of "Hatchers notebook" a number of years ago (lent and never returned) but in there he talks a lot about stability in flight, and gives a formula to work out the optimum length of projectile for a specific twist rate. Not being a physicist but I am sure if I had that formula in front of me I reckon I could work out the twist rate required to stabilise a specific length of projectile. Now that's a project for my spare time.

I have heard from a lot of people that they couldn't get their STI's to shoot, unfortunately over in Aus it's a little difficult to send it back to the factory, that is why we have so many aftermarket barrels available, and no-one I have spoken to has been able to find the manufacturer of the barrels either.

I think we are all aware that the original PPC round was a 148HBWC and it was the foundation of many a great score, and still is. Finding a good manufacturer these days is hard, but they are there and we keep them going strong. With the decline in this style of target shooting (PPC and ISSF) and the rising of IPSC and Action pistol where "fast is best" has lead to a new breed of projectile coming out and the manufacturers catering for that is causing the shortage we all feel. I won't get on the soapbox about powders and primers either.

So optimum twist rate for PPC, does yours work? If it shoots good groups that you are happy with then it's the right twist. If someone gave me a barrel with a 1:50 twist, I have a spare gun to try it on, but wouldn't just go out and buy a barrel because it's there and available. My 1:8 shoots fine, I've shot everything from 100SWC's through 148HBWC's to 160 HBWC's for our Service Pistol match to make power factor, even shot Action with them with some success.

Ultimately, it's the nut on the butt. There is no substitute for skill.

Happy New Year to you all and looking forward to some great discussions this year

Tony
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Joined: August 21st, 2013, 3:31 pm

January 2nd, 2017, 6:36 pm #10

JB
I had no success with anything but the 100gr SWC in my STI, its a 1:24 twist Pulver BBL with a "Nose Cone" bolted onto the front of the barrel and there is no bushing so the end of the slide face locks up against the end of the block on the barrel as you can see below. Very tight lock up and a noticeable clunk when the slide batters forward which takes some getting used to but it will go sub 1.5' off a sand bag.




Andrew,
Interesting that you are able to use the 100 SWC's in this bbl with such good results. Can you tell me what your "load" is for this bullet, COL, etc?. Are you getting reliable function and lock up? Did you "chrono" the loads?
LIke Tony says, STI refused to tell me what bbl they are using other than it is a 1:16 twist.No one else seems to know what they are either.Fairly sure made in Phillipines since their lower end guns made there, but could be in error. The one they replaced it with likes Winchester 115 JHP the most with 4.2 CFE powder, 1.142 COL so far. Cant load it down too much with the weight of slide will not function.You can see slide moving forward almost slow motion, and do clunk on lockup.Does lock up tight. HOw is trigger on yours? Mine breaks about 4.0 lbs no creep.
Just curious, sights appear to be Aristocrat, and wondering if your adjustment screws are metric or s.a.e.? Mine has metric,and Jim @ Aristocrat swears his only come with s.a.e. Had to have the front sight replaced for a higher one for neck shooting at 50. Stock sight could only shoot point at 50, this way it came.
BTW, like the furniture on yours. I picked up a nice set of Rosewood with finger groobs on Ebay made in Phillipines I think.
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