Thread: An Interesting Visit to the Range

Greetings All,
After much procrastination I finally got some chronographing done for my Martini Krag yesterday. As most of you will know load data for some of the older cartridges is all over the place and the .30-40 Krag is no exception. The goal is to get some cartridges sorted for a F-Class 275 metre shoot in the coming season. The rifle is an 1881 Martini with a target weight .30-40 Krag barrel, an old 7.62 barrel cut back 12 inch twist. The Krag cartridge has a bit more capacity than the .308, mostly due to the projectiles being seated well out so an old low pressure load for the .308 was tried. This was 38 grains of AR2206H with the 150 grain projectile. This is about a start load in the Hodgdons Krag data. Just because 40 grains of AR2208 with the 150 grain, also a start load, was tried as well.
I expected around 2,400 fps with the AR2206H load and a little more with the AR2208 load. I expected wrong. Velocities were 2,190 fps and 2,220 fps respectively. Velocity with 38 grains of AR2206H and the 150 grain in my 22" barrel .308 chronographs 2,380 fps. Hmmm. Going back to my notes the Krag case has around 8% more usable capacity than the .308 so will need a little more powder to achieve the same velocity. Some testing will tell.
Just to cap it of I also chronographed a load for a friends rifle to check if there was any difference in a new lot of AR2213SC and got a little too close to the scope. The bump on my eyebrow should disappear quickly. And was there any difference in velocity you ask? Practically nothing at all.
Regards Grandpamac.

Did you get any unburned powder GPM? Also, what brand of brass did you end up using?

Originally Posted by T.FOYE

Did you get any unburned powder GPM? Also, what brand of brass did you end up using?

Greetings,
No unburned powder but it does burn a bit dirty, especially at the 32 grains of AR2206H I use on some soft loads. The cases are some old WW Super .303 cases that I reformed. The cases were unfired with their original primers. The test loads shot a lot higher than my standard soft loads which I have yet to chronograph in the .30-40. In the .303 34 grains of AR2206H produced 2,050 fps with the 150 grain. I have some .30-40 cases that I will use for the final loads. As is often the case the first tests pose more questions than they give answers to but that is the way it is with old cartridges.
Regards Grandpamac.

Not just old cartridges sometimes, having the same problem with a current series Rem barrel 20" .308 in 1-10 twist. Accurate and on roughly at 100m and 200m for a 200m zero, not even on a sheet of newspaper behind the target at 300m. Supposed to be 9" drop off the factory chart, try 24" or more (hard to tell by rough guess and was expecting a left/right windage issue not a dive into the weeds so didn't take a tape measure!).

Thats a 2 feet drop at 300m, WTF? Exactly as you say, more testing required.

Something weird is with this one, as sub loads for this rifle (sub loads being the opposite of super's - velocity controlled by powder amount then length of barrel) require a whole grain of powder less than the 20" 1-12 barrel rifle my friend has as a comparison. Repeat, mine being a 1-10 twist which if the theory works out should have more friction than the usual 1-12" twist. Sub accuracy is fine almost 3 shots touching at 50m and 7" below point of aim which is workable, but the whole grain less of powder indicates that it must be a very 'slick' barrel. Also explains why the 'sub' loads I was getting off a guy a while back were a little louder than expected.

As far as the super's - I am guessing not enough time for the pill in the tube for the pressure to get up to where it needs to, for super loads. Pressure = velocity, rough calculation and all other things being equal. The small amount of reloading I have done for this did not show much promise, it either did not like the pill or the powder or me - and trying to work up a load I got to max on book and max for case full of powder with no signs of pressure but no real velocity to speak of. About 5" below point of impact for the factory load I ended up using and I kind of gave up while I scratched my head and went back to factory...

As you state more testing required - I suspect I may have more success treating it like a 15" "bushpig" barrel, going for one of the powders listed on the faster end for the cartridge and trying to get the pressure curve a bit steeper. My other issue is I am using a Magnetospeed chrony which seems reluctant to pick up the pill when fitted over the suppressor. I need to work out how much closer I need to get the chrony's bayo to the bullets flight path for it to work with the can on and get a decent speed reading off the thing...

Originally Posted by No.3

Not just old cartridges sometimes, having the same problem with a current series Rem barrel 20" .308 in 1-10 twist. Accurate and on roughly at 100m and 200m for a 200m zero, not even on a sheet of newspaper behind the target at 300m. Supposed to be 9" drop off the factory chart, try 24" or more (hard to tell by rough guess and was expecting a left/right windage issue not a dive into the weeds so didn't take a tape measure!).

Thats a 2 feet drop at 300m, WTF? Exactly as you say, more testing required.

Something weird is with this one, as sub loads for this rifle (sub loads being the opposite of super's - velocity controlled by powder amount then length of barrel) require a whole grain of powder less than the 20" 1-12 barrel rifle my friend has as a comparison. Repeat, mine being a 1-10 twist which if the theory works out should have more friction than the usual 1-12" twist. Sub accuracy is fine almost 3 shots touching at 50m and 7" below point of aim which is workable, but the whole grain less of powder indicates that it must be a very 'slick' barrel. Also explains why the 'sub' loads I was getting off a guy a while back were a little louder than expected.

As far as the super's - I am guessing not enough time for the pill in the tube for the pressure to get up to where it needs to, for super loads. Pressure = velocity, rough calculation and all other things being equal. The small amount of reloading I have done for this did not show much promise, it either did not like the pill or the powder or me - and trying to work up a load I got to max on book and max for case full of powder with no signs of pressure but no real velocity to speak of. About 5" below point of impact for the factory load I ended up using and I kind of gave up while I scratched my head and went back to factory...

As you state more testing required - I suspect I may have more success treating it like a 15" "bushpig" barrel, going for one of the powders listed on the faster end for the cartridge and trying to get the pressure curve a bit steeper. My other issue is I am using a Magnetospeed chrony which seems reluctant to pick up the pill when fitted over the suppressor. I need to work out how much closer I need to get the chrony's bayo to the bullets flight path for it to work with the can on and get a decent speed reading off the thing...

Greetings @No.3,
I suspect that either your zero is closer to100 metres or your velocity is low. My bolt action .308 is zeroed at 172 metres to keep the mid range trajectory from being too high and it drops 360mm at 300 metres. Velocity is 2,750 fps in a 22" barrel and 2,700 in a 20" barrel.
Regard Grandpamac.

Yeah, it's zero'd at 200m for convenience (25m, 50m, 100m, 200m and 300m butts) and the 100m is about 1.75" high. 300m drop is in the range of 600mm, which would indicate a LOT slower velocity than what you are reporting (I'd be expecting 2650-2700 from a 20" barrel with 150gr factory loads). In this case, the 150gr load is quoting a muzzle velocity of 2800 from a 24" barrel with a 9.1" drop at 300m with a 200m zero. 2700 from a 20" would be a reasonable expectation, for as you say about a 12" drop at 300 but it can't be doing that.

Greetings again,
You can get some decent velocities from the .308 using AR2206H. 45 grains of that powder with the 150 grain projectile chronographed 2,870 fps the other day in a 24 inch barrel. Book max is 45.5 grains. Even 44 grains chronographed 2,770 fps. In a 20 inch barrel 44 grains of AR2206H chronographed 2,675 fps. 45 grains should give around 2,725 fps even in the 20 inch. Factory loads are often less although I have not fired a factory load for decades.
GPM.

Greetings again,
Back to my OP and the .30-40 Krag. As mentioned in the OP some checking shows that there is a significant difference in net case capacity between the .308 and .30-40 with the latter being about 8% larger based on the Nosler data. In my case the projectiles are set to an overall length of 78.7mm so this may increase the capacity further. For comparison the .30-06 has around 26% more net capacity than the .308. So I should be expecting a little less velocity with my Krag loads. The shape of many of the Hornady projectiles has changed over time with the later shapes producing a little more velocity from my tests, especially with the low pressure loads, something more to check. The camber was cut by Dinny back in 1996 and the projectiles only have about a 3mm jump to the rifling, less than my .308.
More testing is clearly required.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings again,
You can get some decent velocities from the .308 using AR2206H. 45 grains of that powder with the 150 grain projectile chronographed 2,870 fps the other day in a 24 inch barrel. Book max is 45.5 grains. Even 44 grains chronographed 2,770 fps. In a 20 inch barrel 44 grains of AR2206H chronographed 2,675 fps. 45 grains should give around 2,725 fps even in the 20 inch. Factory loads are often less although I have not fired a factory load for decades.
GPM.

Hi GPM,
Heres some factory 3 shot average velocitys of factory ammo fired out of my 308 tika 20in barrell.
Hornday SSTs 150gr=2836ft/s
Hornady SSTs 165gr=2712ft/s
Hornady white tail sp165gr=2575ft/s
This might give you a idea of modern 308 velocity stats.
Trout.

Greetings,
Looks like this .30-40 Martini is going to be another rabbit hole like my search for a decent load for the 6.5x55 a few years back. Excellent. I was poking around on Loaddata.com yesterday and found some loads for the 150 grain and IMR4895 so went and fished out the Handloader issue from the banana boxes. The article was written by Mike Venturino (a favourite author of mine) in 2010 who used a new Winchester 1895 with a 24" barrel together with an older Krag Rifle. IMR4895 is a little slower than AR2206H (H4895) according to the charts so I interpolated velocities from the Hodgdon data for the 44 grain load with the 150 grain projectile and a 24" barrel. AR2206H came out at 2,827 fps and IMR4895 at 2,717 fps. The same load of IMR4895 in Mike's 24 inch barrel produced 2,616 fps in the heavier Remington brass so it would take an additional 2 grains of powder to match the .308 velocity. Aha. It looks like my 38 grain load was softer than I thought. I had used up to 40 grains of AR2206H in my soft .308 loads which would have produced close to 2,500 fps. The only pressure tested data for IMR4595 in the .30-40 dates from the 1970's at the latest and is out of step with the other powders listed so has been ignored. I have not found any pressure tested data for AR2206H but some has appeared recently for AR2208.
So it is back to the loading bench for some more test loads. A report will follow.
Regards Grandpamac.

Always consult multiple sources of data when developing a load.

GPM.