The Firing Line Forums

Go Back   The Firing Line Forums > The North Corral > Black Powder and Cowboy Action Shooting

Reply
 
Thread Tools
Old September 29, 2012, 05:11 PM   #1
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
45-70 BP help - excessive chamber/throat?

Soooo, I just got my 45-70 Pedersoli rolling block and tried to figure out the max possible OAL (I like seating bullets as close to the rifling as possible) and with both my .457 395 grain and .458 520 grainers I get a max length of whopping 2.810''.

I'm fairly new to reloading BP cartridges, my Lee manual says max OAL for the 45-70 is 2.550, I know this is only relevant for lever action rifles etc. but not so much for single shot rifles - but isn't 2.810 a little excessive? I'd have to seat the bullets waaay out exposing more than one of the grease grooves to make the bullet kiss the rifling.

More than half of the 395 grain bullet would stick out of the case that way. (Starline brass)

Last edited by Moloch; September 29, 2012 at 05:21 PM.
Moloch is offline  
Old September 29, 2012, 05:40 PM   #2
Jim Watson
Senior Member
 
Join Date: October 25, 2001
Location: Alabama
Posts: 10,982
Sounds kind of long, all right.
Have you checked the chamber length? Some of the Italian guns came across with chambers longer than 2.1" even though marked .45-70. You might have a .45-90 in disguise.

But you most likely just have a .45-70 with long throat.
I see a lot of BPCR shooters loading grease grooves out of the brass to get the bullet into the rifling, or using tapered bullets to stick grease grooves up into the bore to leave more powder space.

I don't think it matters for target shooting, you can load long and keep your ammo with exposed grease grooves clean.
And for hunting, a jump to the rifling probably doesn't matter much at iron sight hunting ranges.

My Browning BPCR .40-65 only lets me load the front band out of the case mouth, no grease grooves showing.
My Winchester rebored to .38-55 has such a long throat I cannot get up to the rifling at all.
Jim Watson is online now  
Old September 29, 2012, 05:56 PM   #3
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
This is not necessarily going to hurt accuracy? Yeah you are right, try to see the good in everything, it gives me a little extra space for more powder. Those 520 grain bullets need a good push anyway.
Though keeping the exposed grease groove clean and the soft lube in place is a bit of a PITA, just wiping off the excessive lube after seating the bullet and everything is gone.

45-90? That was my first thought, but there is clearly a .45-70 stamped onto the barrel. Whats a good way to measure the chamber length?

Oh, and is it possible that the bullets are simply too small ( .457 & .458) so they crawl deeper into the barrel than a .460?
Moloch is offline  
Old September 30, 2012, 11:39 AM   #4
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
So, here is a round with slightly above suggested max OAL next to a round that almost touches the rifling (2.825):

Moloch is offline  
Old September 30, 2012, 05:24 PM   #5
Jim Watson
Senior Member
 
Join Date: October 25, 2001
Location: Alabama
Posts: 10,982
That does not look as long as the inch measurements made it sound.
I would load them that way and see how they shoot.
You will likely have to increase the BP load to maintain compression of the charge.
Jim Watson is online now  
Old September 30, 2012, 07:51 PM   #6
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
Well,it looks much worse with the 395 grain round nose...



By the way, how you guys can cram 70 grains of black in a modern 45-70 cases is a miracle to me, even with heavy compressing and vibrating the case (works MUCH better than a drop tube) and exposing the first grease groove of the 520 grain bullet I can only get about 56 grains (volume) of swiss 3FG in there - which is a little disappointing. I use Starline brass.

I read some people fill em' up with 65-70 grains without much troubles, I don't know how that is possible - only 5 extra grains in an already compressed load and the primer pops out.

I haven't tried other brands of powder though....
Moloch is offline  
Old October 2, 2012, 01:30 PM   #7
Jim Watson
Senior Member
 
Join Date: October 25, 2001
Location: Alabama
Posts: 10,982
Beats me, I am loading 56 gr Sw 1.5 in .40-65-400 and wonder where the guys are putting 63+.

Seating the 520 grain bullet out a groove is not unusual.

I don't think it matters much where you put the 385, it is not what I have heard of as a precision bullet anyhow. More like woods deer hunting.
Jim Watson is online now  
Old October 2, 2012, 03:10 PM   #8
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
Quote:
I don't think it matters much where you put the 385, it is not what I have heard of as a precision bullet anyhow. More like woods deer hunting
I too heard its not really suited for target work and the barrel twist is probably too fast for a such a lightweight bullet, the original 405 grainer would be a much better choice...but why not, its worth a try I guess.

Anyway, thanks for all the help. Now its time to send them downrange!
Moloch is offline  
Old October 2, 2012, 04:24 PM   #9
mehavey
Senior Member
 
Join Date: June 17, 2010
Location: Virginia
Posts: 2,810
The Pedersoli's are capable of some astounding BP accuracy w/ Postell-type/weight* bullets. But they have to be proper sized (.459).

I'd also suggest 64-65gr Swiss 1½ under such a Postell design/diameter (either Lyman's, Hoch's, or Paul Jones w/ last grease groove just covered) under a 0.62 card wad compressed ~0.17"-ish or so.

Be sure to use a BP-type/soft lube (DGL, SPG, and/or Crisco beeswax & you-name-it)


* 520-540gr


.
mehavey is offline  
Old October 2, 2012, 04:56 PM   #10
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
I'm using 2 parts tallow and 1 part beeswax with 3FG swiss with great success in all my muzzleloaders, extremely clean hot burning powder and the lube leaves the barrel moist from chamber to muzzle. 50 rounds with consistent 100yds accuracy with no cleaning is not a problem and even after months of storage the lube on the bullets doesn't get dry or crumbly.
I'm sure it is going to do an equally good job in my BP cartridge rifle. I think I won't even need a grease cookie.

My current bullets are 520 grain 4 grooves .458, 57 grain swiss 3FG and 62 grain 2FG with very little compression. The bullet touches the rifling, no crimp, Starline brass, Fed large rifle magnum primer.
Moloch is offline  
Old October 22, 2012, 06:39 PM   #11
Moloch
Senior Member
 
Join Date: November 27, 2005
Posts: 1,304
Update!
Made some cartridges with bullets sticking faaaar out of the cases because of the long throat - just touching the rifling - I'm very pleased with the accuracy! It was a busy day at the range and I could only sight the rifle in at 50 firing ~ 25-30 shots, my best load grouped about 1'' at 50, and that was a ten shot group with no cleaning, wiping or using a blow tube between the shots.
I honestly did not expect my my first handloads ever to work that well - in a completely new gun!

The powder fouling was so soft one wipe with a dry cloth and the barrel was shiny again - and that after 10 shots.
I might not even need a grease cookie for future loads.

The 385 grain roundnose bullets loaded with 70 grains of swiss 3FG were a lot of fun, they're not very heavy but they were flying downrange at blistering speeds producing a surprising amount of muzzle blast and recoil, soon a small crowd gathered around me going all ''ooooh'' and ''ahhhh'' after each shot.
They produced 1.5'' groups, I'm sure I can get them down to 1'' with a little tweaking.

Of course, the 520 grainer's were the real deal, while with the slightly reduced charge (58 grain 3fg) not creating as impressive muzzle blasts and smoke clouds they were very accurate.
Judging by the muzzle report they were leaving the barrel at supersonic speeds.

And one fun thing I noticed is that the 520 grainers were so heavy they slightly twisted the 11 lbs rifle in my hands!
I can imagine this to be a more of a serious problem with the 50-100's etc. firing 650+ grain bullets.
Moloch is offline  
Old October 22, 2012, 07:14 PM   #12
Willie Sutton
Junior member
 
Join Date: January 26, 2012
Posts: 1,066
Excellent!

I feel a BP rifle coming on...


Willie


.
Willie Sutton is offline  
Old October 22, 2012, 07:57 PM   #13
drcook
Senior Member
 
Join Date: November 25, 2009
Posts: 237
I have no issues with getting 72 gr of Goex 2F into my cases. I seat 540 grain Paul Jones Creedmores to the first band (right around .650) plus an .060 LDPE wad, so that is right around .710 deep from the case mouth.

It is crammed in there pretty tight.

For me, this has been the best way to get Goex to shoot accurately, ie: compress a lot of powder in. I do the same with the other 45's I shoot. 85 gr of 2F in the 45-90, 98 gr of 1F in the 45-100 and 107/8 gr of 1F in each of the 110's.
drcook is offline  
Old October 23, 2012, 12:01 PM   #14
arcticap
Senior Member
 
Join Date: March 15, 2005
Location: Central Connecticut
Posts: 2,973
Quote:
Originally Posted by Moloch
And one fun thing I noticed is that the 520 grainers were so heavy they slightly twisted the 11 lbs rifle in my hands!
I can imagine this to be a more of a serious problem with the 50-100's etc. firing 650+ grain bullets.

The barrel torque or twisting can be controlled by holding the butt of the rifle as shown in the post below.
The torquing is created by the heavy bullet as it passes through the rifling at high speed, becoming engraved and rotating.
Holding the rifle by the butt also helps to protect the shoulder from felt recoil.

http://thefiringline.com/forums/show...4&postcount=18
arcticap is offline  
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 10:04 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2014 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.09430 seconds with 9 queries