45-70 & 45-90

Highwind

Highwind

CGN frequent flyer
Rating - 100%
5   0   0
Location
Bruce Peninsula, ON
Greetings Big Bore reloaders... I've read some of the older threads on reloading both the 45-70 and 45-90. It seems that there is more data for reloading the 45-70. And it also seems like the 45-90 is a bit more of a rare bird and most (starting) loads are related to the 45-70.

I have a 45-70 but have not developed a load yet and use Winchester 300 gr. factory ammo to get an idea as to how the Marlin 1885C prints the shots on paper. So far I've gone from open sights to a Slug scope. I had to change the rings and mounts as I was not satisfied with the set-up. While the weather may not be ideal now for more testing - I will be more inclined to focus more attention on re-loading this spring.

My question is about the rifle twist and how the bullet weights are matched up as there is a wide variety of bullet weights available in the 458 caliber.

I am also interested in the Winchester Model 1885 as an alternative rifle - so when a 1 in 20" twist is used in something like a Model 1885. I may be leaning towards a 45-90 as a slightly different rifle caliber to use. So how is the bullet weight determined in a 1 in 20" twist...? Or, is it more based on the powder load that is being used that determines the effective (acceptable) accuracy of a 45-70 or a 45-90 in a variety of bullet weights...?

Your responses are appreciated.

Highwind
 
My 458 Win. Mag. and .458 Lott both have 1:14 twist rates and are designed to fire 500gr bullets as standard loadings. My Marlin, Ruger No.1 and Handi-Rifle 45-70's all have a 1:20 twist rate and seem to stabilize 500gr bullets ok to 100 meters because I get < 3" groups.

Not sure about ranges beyond that but for hunting purposes I would limit shots to about 100 meters anyhow at the lower muzzle speeds from the Marlin with 500gr bullets.

There are mathematical equations for determining optimum twist rates -

https://en.wikipedia.org/wiki/Miller_twist_rule
 
Last edited:
The twist is pretty much all you need to look at for bullet stability. I shoot a lot of .45 cal rifles in bpcr/bptr competition. Increasing muzzle velocity doesn't change stability that much. A 1:20 twist will be good to go for bullets in the 500gr range for as far as you care to ever shoot them. You might have trouble with the longer and slightly heavier bullets like the 535gr Postell bullets.

Chris.
 
Speed can make a difference. For example I've tried sub-sonic loads in my 416 Remington Magnum which has a 1:14 twist, and 400gr bullets would not stablize worth a darn. Group size at 100 meters greatly exceeded minute of dinner plate. :p

However, at 1000 meters with my sub-sonic 416 load I could probably keep all my shots within the proverbial broadside of a barn.
grin1.gif
 
Last edited:
Bullet Weight - Rate of Twist - Velocity.

If you know 2 of the variables you can estimate the optimum range for the third. For our purposes velocity generally has such a narrow range that it's mostly not a big factor.
 
I have and shoot a bunch of 45-70's and a couple of 45-90's and what you are looking for in a 45-90 cannot be bettered than the 45-70 you already have. Basically, a 45-70 with smokeless powder can exceed the pressure parameters of most if not every modern gun (that is definitely so for any vintage guns) chambered for either caliber. The only benefit to a 45-90 is if you are using B/P where an honest 200 fps increase over the 45-70 is attainable. To put it another way "any velocity safely attainable with a 45-90 using smokeless is also attainable with a 45-70...And brass is much more attainable for 45-70.,

My 45-70's have a twist from; 2 at 1:20 2 at 1:18 and one at 1:16 and my 45-90's are both 1:20, they all shoot 300 -450 gr boolits within reasonable "lead boolit" accuracy. I once had the pleasure of shooting a vintage Win. 1886 in 45-90 "express" rifled (1:32) gun, Lots of fun with under 350 gr slugs but only key-hole dinner plate accuracy with anything heavier than that.
 
For sporting arms, whatever twist rate that is provided is supposed to produce acceptable accuracy using bullet weights typically used in whatever cartridge -

http://www.exteriorballistics.com/reference/pdf/Twist%20Tables_Rifle.pdf

For example, Remington uses a 1:16 twist rate for their 35 Whelen production rifles and my 700 CDL stabilizes bullets ok up to and including 250gr. Using 310gr bullets, group size at 100 meters increases to around 4" which indicates instability.

My 358 Winchester, which has a 1:12 twist rate, stabilizes 310gr bullets just fine.
 
fingers284 said:
I have and shoot a bunch of 45-70's and a couple of 45-90's and what you are looking for in a 45-90 cannot be bettered than the 45-70 you already have. Basically, a 45-70 with smokeless powder can exceed the pressure parameters of most if not every modern gun (that is definitely so for any vintage guns) chambered for either caliber. The only benefit to a 45-90 is if you are using B/P where an honest 200 fps increase over the 45-70 is attainable. To put it another way "any velocity safely attainable with a 45-90 using smokeless is also attainable with a 45-70...And brass is much more attainable for 45-70.,

My 45-70's have a twist from; 2 at 1:20 2 at 1:18 and one at 1:16 and my 45-90's are both 1:20, they all shoot 300 -450 gr boolits within reasonable "lead boolit" accuracy. I once had the pleasure of shooting a vintage Win. 1886 in 45-90 "express" rifled (1:32) gun, Lots of fun with under 350 gr slugs but only key-hole dinner plate accuracy with anything heavier than that.
Click to expand...

Thanks for all of the comments but I think that fingers284 has answered my thoughts on these two calibers. Given that the perimeter involves a 1 in 20" twist in both rifles. The only difference is the length of the barrels and the Case length size between the 45-70 and 45-90. The thoughts of shooting between the 300 to 450 gr boolits is likely where I will focus my primary efforts. As it would seem to be the most practical for velocity, trajectory and hitting power.

This is all new project stuff for me and I have only recently obtained a Marlin 1885C (22 inch) and have only shot a couple of boxes of Winchester 300 Grain but I am willing to expand into other options. I'm basically interested in a load that will be suitable to an accurate 200 yards out of the 45-70 and a 300 yards out of the 45-90 (which has the longer barrel).

I see that there is a retailer in BC who has some 45-70 loads made up and sells some components to create other load varieties. One of the pre-made loads that caught my interest was a 390gr LRNFP GG. Unsure of the charge so I have only recently inquired about that.

I had initially thought that 350 grains might be close to the sweet spot for velocity and trajectory but unsure about energy. Plans are for Moose and Elk.
 
The 45-90 was originally loaded only with a 300 gn bullet and was given the suffix "express" to denote this. The 1-32 twist was standard in the 86 because that was what was needed to give stability to the 300 gn bullet and the extra 20 grns of black powder was to give the best velocity. The original load for the 45-70 was a 405 gn bullet and Winchester couldn't get enough extra powder in the case to develop significantly higher velocities with the 300 gn bullet so they went to the longer case but seated the bullet much deeper. However, the loaded overall length was more or less the same so one can reproduce the 45-90 ballistics with a 45-70 with bullet weights over 350 grns. In an 1885 with custom throating and twist the 45-90 will match and exceed all 45-70 ballistics with less pressure, or with equal pressures it will better the 45-70 quite a bit.
 
Highwind said:
Thanks for all of the comments but I think that fingers284 has answered my thoughts on these two calibers. Given that the perimeter involves a 1 in 20" twist in both rifles. The only difference is the length of the barrels and the Case length size between the 45-70 and 45-90. The thoughts of shooting between the 300 to 450 gr boolits is likely where I will focus my primary efforts. As it would seem to be the most practical for velocity, trajectory and hitting power.

This is all new project stuff for me and I have only recently obtained a Marlin 1885C (22 inch) and have only shot a couple of boxes of Winchester 300 Grain but I am willing to expand into other options. I'm basically interested in a load that will be suitable to an accurate 200 yards out of the 45-70 and a 300 yards out of the 45-90 (which has the longer barrel).

I see that there is a retailer in BC who has some 45-70 loads made up and sells some components to create other load varieties. One of the pre-made loads that caught my interest was a 390gr LRNFP GG. Unsure of the charge so I have only recently inquired about that.

I had initially thought that 350 grains might be close to the sweet spot for velocity and trajectory but unsure about energy. Plans are for Moose and Elk.
Click to expand...

If you know your velocity and weight you can figure out energy.

Looking at the factory specs for the Hornady FTX, its a 325grain flex tip bullet going 2050fps at the muzzle, with 3000ft/lbs energy. At 200 yards, those numbers drop to around 1500 each. With a 200 yard zero, its shooting 3" high at 100 yards, so point and shoot out to 200+.
 
c-fbmi said:
The 45-90 was originally loaded only with a 300 gn bullet and was given the suffix "express" to denote this. The 1-32 twist was standard in the 86 because that was what was needed to give stability to the 300 gn bullet and the extra 20 grns of black powder was to give the best velocity. The original load for the 45-70 was a 405 gn bullet and Winchester couldn't get enough extra powder in the case to develop significantly higher velocities with the 300 gn bullet so they went to the longer case but seated the bullet much deeper. However, the loaded overall length was more or less the same so one can reproduce the 45-90 ballistics with a 45-70 with bullet weights over 350 grns. In an 1885 with custom throating and twist the 45-90 will match and exceed all 45-70 ballistics with less pressure, or with equal pressures it will better the 45-70 quite a bit.
Click to expand...

Thanks c-fbmi for your response. When I was thinking about the comparison I had a few thoughts in mind... Some of which I have stated and some that/ I have thought about since my earlier 2 posts in this thread.

So it would be a scenario like this: 45-70 with a 350 grain bullet @ 2000fps. And a 45-90 with a 350 grain bullet @ 2100 or possibly 2200 fps. The other scenario might be a 390 grain bullet with a higher load of powder in the 45-90. I'm thinking about how the 45-90 can offer a tad more velocity due to the larger case capacity, and longer barrel. Where the 45-70 has a 22 inch barrel and the 45-90 has a 28 inch barrel.

Incidentally, with the notion that the 45-90 case may produce less pressure then the 45-70 has my interest - among other variables.

Also, thanks Suther for your comments as well.

Highwind
 
Suther said:
If you know your velocity and weight you can figure out energy.

Looking at the factory specs for the Hornady FTX, its a 325grain flex tip bullet going 2050fps at the muzzle, with 3000ft/lbs energy. At 200 yards, those numbers drop to around 1500 each. With a 200 yard zero, its shooting 3" high at 100 yards, so point and shoot out to 200+.
Click to expand...

For informational purposes I found some information that you may find interesting: http://www.ballisticstudies.com/Knowledgebase/.45-70+U.S+Government.html

The most recent addition to the .45-70 factory ammunition line up is Hornady’s 325 grain FTX Leverevolution. Rather than a flat point, the Hornady bullet features a pointed bullet with a rubber tip to prevent detonation when loaded into tube loading magazines. Hornady advertise a very hot velocity of 2050fps for their FTX load from a 24” test barrel. In 24” sporting length barrels, velocities average 1820fps (still good for factory ammunition), around 1750fps in 22” sporters and 1650fps in the Guide Gun.

Unfortunately, although the FTX bullet is advertised as having a flat trajectory because of its pointed design, its BC’s are simply no higher than other round nose .45-70 designs. The result is that this bullet offers nothing over traditional 300 grain factory offerings and the FTX tends to be identical in both wounding, speed of killing and penetration

Also more interesting information from: http://www.opticstalk.com/45-70-marlin-which-barrel-length-is-better_topic13646.html

"I went out and marked 100 yards 150 yards and 200 yards. I shot all three 45/70s 18.5 in 22 in and the 24 in. depending on the bullet you shot this is what I found out.
the 18.5 is a great rifle 100-125 yards great 125 plus yards it drops fast.
the 22in like I said depending on the round was better no problem hitting 200 yards with about 7-8 in drop.
the 24 in was the best over all 100 yards 150 yards 200 yards very accurate with about a 4-6 in drop at best.
I used buffalo 300gr 350 gr Hornaby 325gr and garrett 420gr for my little test.
with that said and reading all the replys .
I think the 22 in and the right round would be best over all and even better if you could get it in stainless.
the xlr is great to . For a brush rifle its a little long barreled for me."

I have the 22" barrel but remain open to the 24".
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom