Barrel twist help

[M-Tecs]

I am in the process of build two BPCR/BPTR rifles. Both will be on original Winchester High Wall actions. One will be 45/70 and the other will be 45/100 or 45/110. The barrels will be Krieger Stainless Steel.

At this point I am not sure what chambers and if I will paper patch or use greasers but I do have to decide on the barrel twist to place the order.

What do you recommend for twist 16, 17 or 18?

Also Krieger offers the standard 70/30 land and groove or a 50/50 land and groove that they recommend for lead only. Thoughts on land and groove width?

Thanks in advance and I am posting this question on multiple forums.

[Outpost75]

What bullet do you plan to shoot? A 20" twist in .45-70 stabilizes the service 500-grain bullet to 1000 yards....

[M-Tecs]

I am unsure at this point. I am coming over from the NRA High Power and F class competitions and I am trying to determine what the most competitive setup will be.

[Chill Wills]

All three are winners with a good history of working well. My guess is you will end up with a bullet in the 540 - 555gr weight range. the slower 18 twist will shoot this length bullet well. I have been happy with the faster 16 in a few of my LR rifles but to tell you the truth it is so hard to really know. You shoot one rifle one day and a different another day and we just get an impression. I've done well with both and poor with both. That just describes our luck with the conditions we got at times. Having this very debate with myself I had a 17 twist PP rifle made just because I had the barrel.

If you can order something-(as in anything you want) I think I would go faster. It will help with the more difficult conditions like wind sheer -more than one wind direction that the bullet encounters on the way to the long targets. The draw back is that you will have slightly more high and low impact with the faster twist when you get switching conditions - as in having to make shots in a changing wind that runs from one side of zero, then from the other side and so on, on consecutive shots . If this does not make sense I can go into it a little more in depth. It is hard to describe this in few words....

A 17 is in the middle :D

Really - you can't go wrong with any of them. As you know - Trigger time and match time are the biggest way to put points on the scorecard.

[kokomokid]

Adding to what Chill said I am happy with my 17 twist wide land and 540 grain for bpcr. My Krieger wide land is not a 50/50 but I have seen them in 40-65?

[BrentD]

M-Tech, I put a long answer to your question on bpcr.net. But the short answer is 16 twist does seem to have a definite advantage at 1000 yds. At silhouette and midrange distances, the 18 twist will do just fine, but the 16 is no handicap. If they are both as similar as possible, then using them as back-ups for each other will be an additional benefit.

I would not consider any case bigger than a .45-90 with groove diameter bullets and nothing bigger than .45-70 for paper patches, regardless of the distance. 100s and 110s are just too much of a good thing. Way too much. I've been there, done that over and over and there is just no reason for it other than you just like 'em. You won't win more matches because of them and you might lose a few.

[MBTcustom]

Faster is always better if you can get away with it, and with this caliber, you can. I would go 1-16.
Stick with the 50/50 land/groove.
If there is any possibility of getting a tight bore, do so (more land height/groove depth what-have-you).
Longer is better if you can handle it.
The #1 thing you can do for accuracy, you have already done. You're buying Krieger.

[Don McDowell]

I think the 16 twist might just be the way to go. If you're not absolutely stuck on a Krieger barrel, you might want to consider having one built by Oregon Barrel. I had them make one in 44 caliber with a 16 1/2 twist that is shooting very well and to date have not plucked any lead out of it yet. The smith that put it on my rifle said it was about the smoothest barrel he'ld ever worked with.

[Lead pot]

I have barrels with 1/16, 1/17, 1/18 and 1/19. I haven't had much time with the 1/16 ROT for long range yet so the jury is still out with the 16. The 1/17 is shooting very well.

Good Steel.

I will argue with the deeper the better groove. I have a mistake barrel that was supposed to have a .438/.446" bore/groove and it ended up as a .438/.4495. It gave me larger then basketball groups at 200 yards with all loads and bullets I have. The barrel maker replaced the barrel with the proper dimensions.
Later I gave it a thought to see if I could buy the bad barrel back and I did at a reduced price to see if I can make it shoot. I spent a couple weeks making brass lapping slugs so I can just lap the land tops to a larger bore diameter. I gained .002, one thousand per side and for the final lap I made some hard bore sized mono type slugs and used them for fire lapping with 400 grid Clover.
After cleaning the bore I shot 10 PP rounds at 200 yards and the group has shrunk down to 5" with out developing a load. I made a new brass lap slug and went at it again and now the extreme vertical is gone.
I would sooner have a groove that is shallow like .003" then one that is deeper then the normal .004"
Leave the .010" deep groove for the muzzle loaders with patched round balls. :)

[Don McDowell]

Just got a reply from OBC about my inquiry to duplicate the outside contour of the Browning bpcr barrel, and :D they said they can and will do it, just send them the measurements and they'll give me the cost... Here comes a 45-90 16 twist paper patch gun...

[Gunlaker]

Don have you thought of going to a #5 weight barrel and reworking the forearm? Mine has a 32" #5 barrel and I think it helps tame the recoil. I'm getting 1370 fps with the 446535 bullet ( and about 25 fps less with Swiss 1.5 ). It's a lively little rifle :-)

Chris.

[Don McDowell]

Chris this CPA has a 5 barrel on it, and it sure tames the beast down. I have sort of thought about it, but I hate to bugger up the forearm on this Browning, in the off chance I want to turn it back to 45-70.

[Gunlaker]

That makes sense :-)

[MBTcustom]

I have barrels with 1/16, 1/17, 1/18 and 1/19. I haven't had much time with the 1/16 ROT for long range yet so the jury is still out with the 16. The 1/17 is shooting very well.

Good Steel.

I will argue with the deeper the better groove. I have a mistake barrel that was supposed to have a .438/.446" bore/groove and it ended up as a .438/.4495. It gave me larger then basketball groups at 200 yards with all loads and bullets I have. The barrel maker replaced the barrel with the proper dimensions.
Later I gave it a thought to see if I could buy the bad barrel back and I did at a reduced price to see if I can make it shoot. I spent a couple weeks making brass lapping slugs so I can just lap the land tops to a larger bore diameter. I gained .002, one thousand per side and for the final lap I made some hard bore sized mono type slugs and used them for fire lapping with 400 grid Clover.
After cleaning the bore I shot 10 PP rounds at 200 yards and the group has shrunk down to 5" with out developing a load. I made a new brass lap slug and went at it again and now the extreme vertical is gone.
I would sooner have a groove that is shallow like .003" then one that is deeper then the normal .004"
Leave the .010" deep groove for the muzzle loaders with patched round balls. :)

Great post Lead pot. However, I was thinking more about .0045-.005.
.006 is pretty egregious.

[frnkeore]

Regarding rifling styles, if you use a bore riding bullet, the 50/50 will be better but, if you use a bullet with that just has groove size bands, the wide lands will distort it and take more pressure to engrave the rifling when loading out.

Frank

[Don McDowell]

In the letter from Bodine to the Sharps co, that Seller put in his Sharps rifle book, there's an interesting snipit on Bodine's thoughts about rifling depth.