Barrel twist 40-65 for silhouette

Discussions of powders, bullets and loading information.

Moderators: Kirk, Lucinda

schmidtzen
Posts: 8
Joined: Mon Feb 03, 2003 10:19 pm

Barrel twist 40-65 for silhouette

Post by schmidtzen » Tue Jan 14, 2020 8:03 pm

I've been considering a #1 sporter rebarrel from 45-70 to 40-65. I have a choice of a 1 in 14 twist or the standard 16. Either one would be a Shiloh barrel. Is one easier to find bullets that they like?

John Bly
Posts: 845
Joined: Thu May 13, 2010 12:32 pm
Location: Stephens City, VA

Re: Barrel twist 40-65 for silhouette

Post by John Bly » Tue Jan 14, 2020 8:20 pm

I've been shooting a #1 in 40/65 with a 16" twist for quite a few years now. It is perfectly adequate with bullets up to the 416 grain Brooks Creedmoor that I mainly shoot. I've shot master scores with it in silhouette, not as many as I would like but it is the chickens' fault. I shot a 294 with it in mid-range which would win most matches but got beat with a 295. It should be easy to find bullets that perform well in a 16" twist barrel.

I got a 40/70 SS last year with a 14" twist but have not been able to wring it out yet. I have a 425 grain and a 442 grain bullet that I hope to get shooting in it. A 14" twist will handle heavier bullets better but still give good accuracy with bullets in the 400 grain range.
"Perfection consists not so much in doing extraordinary things as in doing ordinary things extraordinarily well"

Coltsmoke
Posts: 1093
Joined: Sun Jul 04, 2010 8:55 am
Location: GA.

Re: Barrel twist 40-65 for silhouette

Post by Coltsmoke » Tue Jan 14, 2020 8:37 pm

16 is all you need.
Swamp Man Shelby Stanza for President!!

SSShooter
Posts: 2274
Joined: Mon Feb 20, 2012 7:06 am
Location: Jersey Shore

Re: Barrel twist 40-65 for silhouette

Post by SSShooter » Tue Jan 14, 2020 8:42 pm

The 14.5" twist of my 32" 40-65 barrel shoots a 440gr BACo Money bullet just fine when pushed by 65gr of Swiss. Even knocked over 15 rams in a row once upon a time. The faster twist will shoot anything that the slower twist will shoot. The converse is not necessarily true.
Glenn

TexasMac
Posts: 1744
Joined: Sun Nov 04, 2007 5:29 pm
Location: Central Texas
Contact:

Re: Barrel twist 40-65 for silhouette

Post by TexasMac » Tue Jan 14, 2020 9:48 pm

I second Glenn's comments. BTW, the .40-65 #1 Sporter with 30" barrel I received last year has a 14.5 twist although I ordered a 14 twist. It shoots great.

Wayne
NRA Life (Benefactor & President's Council) Member, TSRA Life Member, NSSF Member, Author & Publisher of the Browning BPCR book
http://www.texas-mac.com

BFD
Posts: 2374
Joined: Mon Jan 21, 2008 7:36 pm

Re: Barrel twist 40-65 for silhouette

Post by BFD » Wed Jan 15, 2020 6:53 am

go with a 14" twist and you will never regret it.

beltfed
Posts: 1473
Joined: Sun Jun 03, 2007 10:07 am
Location: Central Wi

Re: Barrel twist 40-65 for silhouette

Post by beltfed » Wed Jan 15, 2020 9:14 am

Though I have had very good results with my 16 twist 40-65,
I would definitely go with a 14.5" twist if I build another one.
beltfed/arnie

40-65rl
Posts: 142
Joined: Thu Nov 20, 2014 10:44 am
Location: cheyenne, wy

Re: Barrel twist 40-65 for silhouette

Post by 40-65rl » Wed Jan 15, 2020 10:42 am

So if I was shooting 410 gran bullets would it be okay to have a 1-16? Should I have a 1-14 if I go to heavier bullet, say 430?
thanks
Dick

TAA
Posts: 226
Joined: Thu Oct 16, 2008 9:22 am
Location: St. Paul, MN

Re: Barrel twist 40-65 for silhouette

Post by TAA » Wed Jan 15, 2020 11:36 am

It also helps to consider the length of the bullet as a function of barrel twist rate.

My rifle is chambered in 40 cal 2 1/2 (Sharps straight). I have a Paul Jones Money bullet that is 1.494” long. My Badger barrel is a 16 twist. The muzzle velocity of the 416-grain bullet is about 1,323 fps. I’ve had some good advice on the bullet length subject suggesting that 1.494” is too long for 16 twist unless I push the mv to 1,400 fps and use a 14.5 twist.

If a person wants to play with longer bullets, there is nothing to lose by going with a 14 twist. Today’s favorite bullet might not be tomorrow’s favorite bullet and if tomorrow’s bullet is on the long side, having a faster twist available makes sense.

Tom

martinibelgian
Posts: 1371
Joined: Thu Oct 26, 2006 1:20 pm

Re: Barrel twist 40-65 for silhouette

Post by martinibelgian » Wed Jan 15, 2020 11:41 am

To put it simply, too fast a spin is by far the lesser evil. If you use too long a bullet in too slow a twist, the bullet will become unstable, losing accuracy and might even tumble. Using too fast a twist - within reason - will just increase your flexibility as to bullets used, with little or no accuracy loss. In other words, it keeps more options open.

SchuetzenDave
Posts: 720
Joined: Mon Jan 07, 2013 9:07 am
Location: St. Albert, Alberta

Re: Barrel twist 40-65 for silhouette

Post by SchuetzenDave » Wed Jan 15, 2020 12:31 pm

You need a barrel that will have a gyroscopic spin factor (Sg) of 1.4 to 2.0.
Long range shooters will overspin their bullet (Sg> 2.0) to compensate for drag over 1,000 yards.

For a 16:1 twist barrel the Sg for the .40 caliber BACO bullets are:
400 grain Money 1.94
415 grain Postell 2.14
420 grain Money tapered first band 1.85
420 grain Spitzer 2.17
430 grain Credmoor 2.15
430 grain Creedmoor tapered 1st band 2.15
430 grain NASA 2.20
444 grain NASA 2.10
460 grain Money tapered 1st band 1.76
460 grain Creedmoor 1.83

So there is not much need to spin the bullet even more with a tighter 14:1 twist.

40-65rl
Posts: 142
Joined: Thu Nov 20, 2014 10:44 am
Location: cheyenne, wy

Re: Barrel twist 40-65 for silhouette

Post by 40-65rl » Wed Jan 15, 2020 3:29 pm

I am shooting a 40-65W, Mike Lewis creedmoor bullet, 1.372 length, 430 grains in a 1-16, 28 inch barrel at about 1275 fps. 60 grains of fffg Swiss with little compression. Have not seen any tumble at 600 yards on paper targets and none at 500 on metal rams. and will not be shooting it pass 600. What do you guys think? OK?

SchuetzenDave
Posts: 720
Joined: Mon Jan 07, 2013 9:07 am
Location: St. Albert, Alberta

Re: Barrel twist 40-65 for silhouette

Post by SchuetzenDave » Wed Jan 15, 2020 5:00 pm

Caliber 0.409 Inches
Bullet Weight 430 Grains
Bullet Length 1.372 Inches
Barrel Twist 16 Inches/turn
muzzle velocity 1275 fps
Temperature 50 degrees Fahrenheit (59 is standard)
Pressure 29.92 inches of mercury (29.92 is standard)

Sg = 2.27

You are slightly overspinning the bullet.
It will stabilize and shoot well, even past 1,000 yards.
The Creedmoor nose will also have good dynamic stability at long range as well.

User avatar
Shadow 4
Posts: 275
Joined: Sun Aug 19, 2007 9:41 pm
Location: Big Sky Country

Re: Barrel twist 40-65 for silhouette

Post by Shadow 4 » Wed Jan 15, 2020 7:04 pm

Information is on the lid.
seems like it works pretty well on silhouettes when asked :wink:
it's a 16 twist hi wall
Case heads are hits :lol:
Shot all same afternoon, from a chair :wink:

This is a BACO 420gr mold, might have gotten it when they were mislabeled, because information wasn't matching up, as some clarification on the phone as to what I was actually going to get. Either the description was right & the picture w/part# on pic was wrong, or the other way round. Check back when Texasmac brought it up on this forum. It was before that as you can see in the upper right corner, they were cast in 2018, would have been January-March sometime. I bought it well before that date, might have been in 2017, before I got around to using it in 2018, maybe :roll:

Image40 65 9 17 18 PAT TAYLOR METHOD by Brian Hickey, on Flickr

target is NRA official 1000 yd 6'x6' steel, with a 8, 10 & X ring 3D
Image2018 world champ (1) by Brian Hickey, on Flickr
A GUN LIKE ANY OTHER SOURCE OF POWER IS A FORCE FOR EITHER GOOD OR EVIL BEING NEITHER IN ITSELF BUT DEPENDENT UPON THOSE WHO POSSESS IT

40-65rl
Posts: 142
Joined: Thu Nov 20, 2014 10:44 am
Location: cheyenne, wy

Re: Barrel twist 40-65 for silhouette

Post by 40-65rl » Wed Jan 15, 2020 8:01 pm

Thanks Dave.
Knew that bullet really kills rams.
Think I’ll send it out a a creedmoor match and see what happens.

Post Reply