OK something new 45-70 Question

[.30carbnut]

Hello all. I have been studying the 45-70 cartridge and firearm for long range for about 5 years. I have built my first rifle in .30 WCF from scratch (Check out my thread on special projects) that I took around 3 years of studying to gather information about how to do it, now I want to build a long range 45-70. The question is about rate of twist, number of grooves and barrel length. All of my research has led me to a 28"- 30" barrel with a 3 groove 1:18" twist. What would be your suggestion? I plan on this being a 45-70/80-500 Lead boolit load in a 2.4" case. Thanks in advance for any input.

[ian45662]

1:16 is a fabulous twist for the 45-70. Green mountain also makes a great barrel but the 45-70 is a 2.1" case. A 2.4" case would be a 45-90

[.30carbnut]

If you are intrested in the long range shooting of the 45-70 You should read this it is lengthy and is the best information I have found on long range Shooting for the 45-70. http://usarmorment.com/pdf/45-70.pdf
Are you basing your recommendation on a lever action or a single shot falling block? My rifle will be based on a falling block design. Thank you for the input.

[ian45662]

I am basin it off my own experience with my c sharps highwall. Although I have not shot 1000 yards with it I shoot it a good bit out to 550 yards in bpcr silhouette competition It loves a 540 grain creedmoor bullet and on paper at 200 yards will shoot under an Moa routinely. Like I said I have not shot it out to 1000 but I do know people who do shoot and love the fact the the 1:16 twist in a 45-70 allows a person to shoot long heavy bullets at distance. Trapdoors like the ones that were tested in the link you posted have a 1:22 twist. Pretty slow by today's standards but 1:18 would be alright The 1:16 will allow you to shoot slightly longer and heavier bullets.


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[.30carbnut]

Thank you for the information it will be very useful. The long range Springfield rifle that they were using had a 33" barrel with a 3 groove and 1:18 twist and this is what I have based my observations on, thus why the questions, looking for all of the knowledge that I can get From real experience with the cartridge an rifle.

[ian45662]

Right and it was a 45-80. Had a longer case than the 45-70. Standard trapdoor 45-70 has a 1:22 twist but based on those tests Springfield adopted that projectile for their 45-70 in 1881 and in 1884 started making rifles with sights that would calibrate with the new bullet but kept for 1:22 twist.


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[country gent]

Both my 45 cal BPCR rifles are 1-18 twist and stabilize a 550 grn Old West Bullet. One is 45-70 with a pedersoli barrel and the other is 45-90( 2.4"case) and green mountain barrel. I believe the chamber, throat, and leade are more important to an accurate rifle. But the 3 groove barrel is interesting. Also Kriegers is making an Alexander Henry rifling form blank now in 1-18 and 1-16 twists, I believe it is 6 groove.

[.30carbnut]

Great Information from all Thank you. Does any one have any experience or comments on PAC-NOR and McGowen barrel quality?

[country gent]

I have a Mc Gowen on My High Wall in 38-55 that's a accurate easy to clean barrel

[Randy Bohannon]

Pac Nor and McGowen are top shelf barrels