45-70 twist

[Gunlaker]

The good news is that the original poster's 1:18 twist Green Mountain barrel will be fine . That is pretty much the standard for .45 cal twist rates at Silhouette distances for single shot rifles these days. Any garden variety 525-535gr bullet that fits well will shoot pretty well.

I am also with Brent on the faster twists. However, my long range rifles are 1:16 twist not because I have done extensive experiments myself, but rather because I look at those who are beating me and I observe what they are using before buying my next rifle. 1:16 twist .45 cal rifles aren't always at the top for LR, but they sure seem to be there very often.

When I bought my first 1:16 twist .45 cal rifle ( a .45-2.4" paper patch only rifle ) I expected it to shoot noticeably worse at shorter distances based on internet wisdom. That was certainly not the case as it, ( and my other fast twist .45-90, and a fast twist .40-65 ) all have excellent accuracy at any distance I've shot them at. At least as good as my slower twist rifles, and often better.

Chris.

[BrentD]

Chris, if it shoots well at the longest range, internet "wisdom" notwithstanding, it will shoot well at short range too. It has to.

Most 535 bullets will shoot well enough in an 18 twist, but there are bullets of that weight that are over 1.5" long and those are too long for 18" at 1000 yds in my opinion and I have done it lot. Even won with it once, but that was luck and necessity, not skill and good planning. I would not exceed about 1.46" for a 1000 yd bullet in an 18 twist. And even that may be a little edgy, depending on the shape of the bullet.

[Chill Wills]

There are stability and twist rate calculators on the web that are easy to use.

They will normally want the length of your bullet.
They may calculate a stability factor, a twist rate or the bullet length.
Goof around with a few of them and you will see what I mean.

I kind of like this last one.

http://www.geoffrey-kolbe.com/barrel_twist.htm

For fun I tried the third one offered. I used a 45 cal BPCR bullet I had made up about 2004 and entered the data as close as the fields would allow. I think I did it right.
http://www.geoffrey-kolbe.com/images/151038.png
I don't think the graph will show up but the result shows a 22 twist up to the speed of sound and then faster than... a 26" then a 25" is best.
Hmmm...
So, what do I know anyway????????

Bullet diameter (inches) .459
Bullet length (inches) 1.465
Nose length (inches) 0.7
Meplat diameter (inches) 0.23
Base diameter (inches) .459
Boat-tail angle (degrees) 0
Boat-tail length (inches)
Barrel twist (inches)
Secant nose radius (calibres) 6
Specific Gravity (gms/cc.) 11.4

Air temperature (Fahrenheit) 59
Relative humidity (percent) 0
Atmospheric Pressure (in. Hg) 29.92
Barometric Pressure (in. Hg) 29.92
Altitude of range (feet) 0

[Edward]

You are a smart lad, I'm sure you will figure it out, but to be helpful, if it is someone that looks like you, it's not me or another shooter - it's a mule. Work it out from there...

Now that there"s FUNNY

[Gunlaker]

Brent I've never seen a 535gr bullet quite that long. My molds in that weight range are all 1.46" and shorter.

I do have a PP money bullet by BACO that is 1.51" long, but it's a 545gr bullet. I won a gong match with it once in a 1:18 twist .45-110 out to 900 yards, but I generally use shorter bullets. Even in my 1:16 twist .45's I have been keeping them shorter than 1.5" on the advice of a fellow who wins more than his share of Creedmoor matches. Better to have an overly stable bullet than one slightly under stabilized.

Chris.

[Chill Wills]

I hate to sound like a know it all but I doubt if more than a very few shooters can tell what twist they are using (likely none) and fewer among the top ten longrange BPCR riflemen in the country would place any differently using an 18T, 17T or 16T 45cal. given the bullet is not a mismatch to the twist.

As I am sure you would agree ....Skilled riflemen place high in most matches. Conversely, inexperience in tough conditions shows up on the scoreboard. If you are good, the wind is your friend.

At best, we get an impression of what we like and what works.
And the calculators make for night time entertainment.

[Gunlaker]

As I am sure you would agree ....Skilled riflemen place high in most matches. Conversely, inexperience in tough conditions shows up on the scoreboard. If you are good, the wind is your friend.

This is the nice part about rifle shooting in general, and BPTR in especially I think. The only thing I'd add is that a good spotter can make a mediocre shooter look good, and a terrible spotter can sink a good shooter so you mostly need both.

Your line about the wind being your friend reminds me of how often I have heard of people complaining of even moderate mirage at the range. Light to moderate mirage is one of the best gifts to a shooter.

Chris.

[Chill Wills]

The only thing I'd add is that a good spotter can make a mediocre shooter look good, and a terrible spotter can sink a good shooter so you mostly need both.
Chris.

The fact that NRA Creedmoor is a team event is why I have taken a break from mid and LR events the last few years. Odd that most all other target rifle sports to include youth 22rf, the competitor relies on themselves only, and to be coached would be cheating. None of the International BPCR matches and the LRML allow coaching. A few team events, country v country matches do however.

So my question is, why do North American BPTR riflemen have such low confidence in their ability that they need a coach to tell them which way and how much to turn the knobs?

I go to the matches to win. Our NRA matches require you bring a darn good spotter/coach with you to make the wind calls for you because if you are working alone, you are up against pairs of champion wind callers working together.
That system is not wrong, if you need that. I just prefer one competitor, one rifle working alone like 99% of all other matches shot around the world.

Sorry if I sound Like I am in rant mode

I would propose a rule change to allow coaching in the lower classes and make Expert and Master class shoot with out help. Not only would that level the field a little, it would solve the score-keeping issue too. It is the whole reason I started the American Creedmoor Cup.

Okay - I pounded this OT enough here.

[Lead pot]

Chill you don't sound like a rant, I agree with what you said above.
I never have shot at a National match. I like the gong and local and regionals long range and silhouettes. A lot of matches are won by the coaches ability to keep his shooter in the scoring rings. Mostly the high score is shot is by the ability of the coach behind the spotting scope telling the shooter where to hold or twist the knobs.

[Gunlaker]

I agree Chill. Although it might make the sport harder to get into for someone not experienced with wind reading.

I wonder if the spotter/shooter team idea was a carry over from silhouette? It's much harder, with black powder, to spot for yourself in silhouette. With a scope it's doable but with aperture sights it would be really hard.

Chris.

[Don McDowell]

I really enjoy the "Creedmoor Cup" style matches. The ones at Lodi and Byers are a great challenge.
I do have to note tho that usually the shooters in the high end of scores in the "Cup" are usually the same ones battling it out in the top of the "team" matches.

[Lead pot]

The shooters on to top of the finish line with out coaching or even being coached have the loads worked out and can control their rifle to get the best out of their rifle and load.
You can take one rifle and load and let two shooters shoot that rifle and load and you will see one shooter better than the other.

[Outpost75]

I thought TDs have a 1:22 twist.

I checked checked my references and you are indeed correct and I appreciate the correction. It can be dangerous to rely upon memory once you get past age 70. Thank you!

But for the purpose of answering the OP, his 18" twist is more than ample.

[Don McDowell]

The shooters on to top of the finish line with out coaching or even being coached have the loads worked out and can control their rifle to get the best out of their rifle and load.
You can take one rifle and load and let two shooters shoot that rifle and load and you will see one shooter better than the other.

Not necessarily Kurt, I will agree that familiarity with a given rifle is a plus, but if you watch those shooters that consistently are in the hunt, with or without spotters, they spend more time in the scope than they do in the gun. Wind and mirage can truly be a shooters friend.

[EDG]

So you have a BPCR shooter who touts his skill yet has never been able to figure out what he thinks is the best twist? Blaming the twist calculators for having errors is strange. It is so easy to prove your point by merely rebarreling your rifle and winning all subsequent matches you shoot in.

Now that there"s FUNNY

[Don McDowell]

I think Chill Wills hit it pretty good on the twist thing in post 26.
I have no experience with a 16 twist in the 45-70 but I have rifles in 45-90 with 16 and 18 twist, and outside of the difference in the chambers between the two allowing for different overall cartridge lengths there is not a lot of difference, except for the 16 twist rifle will shoot bullets under 530 grains better than the 18 twist all the way to 1000. Still scratching my head on that one.
Also while it goes against conventional wisdom an 1884 trapdoor rifle will shoot heavier bullets like the Lyman postel, and the RCBS 82084 better at 1000 than a standard government bullet.
I guess the moral of the story was as Crossfire Oops once said, figure out what the gun you have likes and run with it, and forget about what you wish it had...

[Chill Wills]

I agree Chill. Although it might make the sport harder to get into for someone not experienced with wind reading.

I wonder if the spotter/shooter team idea was a carry over from silhouette? It's much harder, with black powder, to spot for yourself in silhouette. With a scope it's doable but with aperture sights it would be really hard.

Chris.

I would point out a few of my observations.

You write:Although it might make the sport harder to get into for someone not experienced with wind reading.
I agree, which is why I would suggest only making Expert and Master class in BPTR a NO Coaching zone and by all means the Marksman and Sharpshooter class could have a coach. I would not want to discourage new entry.

Again you write: I wonder if the spotter/shooter team idea was a carry over from silhouette?
Likely yes when BPCR was reorganized (NRA) in the second half of 1990's do to the sudden popularity of BPCR-Silhouette, but LR BPTR matches had never really gone away, with no one governing body the rules were somewhat local. Canada has a long history too. Europe and British countries around the world post WWII.

"It's much harder, with black powder, to spot for yourself in silhouette."
Indeed. I would not even propose a change in that event. It will always remain a team match. However, if, when at the start of BPCR-Silhouette in the middle 80's it was agreed on that you only get a spotter to locate the shots and not coach, no one today shooting the game would know better. That would just be how the game was played. Interesting enough in target rifle matches, the puller in the pit has the same roll as that spotter just described for silhouette. They mark the shot placement but do not coach. Anyway, silhouette will not change and that is fine.

[Chill Wills]

I really enjoy the "Creedmoor Cup" style matches. The ones at Lodi and Byers are a great challenge.
I do have to note tho that usually the shooters in the high end of scores in the "Cup" are usually the same ones battling it out in the top of the "team" matches.

Yes, if you want to win, we instinctively know it is only to our advantage to find the very best partner we can find to shoot with. Great riflemen find great riflemen to work with. As we know, that is why working alone is such a big disadvantage as I did in 2014 in mid-range championship. I won the first day on my own but lost out the overall by one point to Rick Moritz and Jack Odor sorting out switching conditions in real time and shooting fast. It is very had to compete against two very skilled riflemen working together. Should we really need to?

BTW-Don, I may have some the info you emailed me about. Let me know what you want. I hope your snow drifts are melting - but!!!! you should shoot a few test bullet into them while the piles are big.

[Don McDowell]

One of the most notable things I heard at the 2018 nationals, was when you told Jack in those switching winds, " well it looks like in these conditions each shot is like starting a new match". Truer words have seldom been spoken, and it's just something one has to experience from the firing line and not on the internet....
Being a good/great rifleman doesn't always mean that same person can be a decent spotter, and it is sometimes frustrating especially in silhouette when the spotter can't accurately locate the shots, and tends to go by the dust in the berm,, that can cause a whole series of misses, and one of the reasons I really like to set the targets, then I can see first hand whether my shooting or missed shot locations were the bugaboos.
The one thing I would sort of like to see in the "Cup" matches is for the pits to be able to give a general location of a miss. At Lodi I wasn't able to tell where the misses were going in the middle of the string, and later found out I was just high off the target and shot the living snot out of those little aluminum rectangle things they have mounted just above the target frame.
Would love to do some shooting, the snow is disappearing in places, but those places are ankle deep in mud, and it's a tough go to get thru the drifts to find those spots. Matter of fact I have a new rifle that has been patiently waiting for a month to get sighted in..
I will email you shortly.

[BrentD]

Michael, if you don't like the coaching aspect you should be all over long range muzzleloading. No coaching there. Ditto lever gun where the spotter simply spots. Of course wind corrections are pretty trivial in lever gun.

But take up the muzzleoader again. I know you have been there before. It's a one-man game all the way.

Personally, I like the teamwork of paired shooters/spotters. It is part of what makes the match enjoyable. But I like the muzzleloader matches as well. So, I just shoot them all.

Leaving for Oak Ridge in 3 days.