Confused About 30 - 40 Krag Cartridge Length

[cpuwhiz11]

Hi all,

I started reloading for the first time some 30 - 40 Krag and I am very confused when it comes to the length of the cartridge. I am using the Lee reloading data from Modern Reloading. It specifies that the maximum overall length for a loaded cartridge should be 3.089 inches. Yet, looking at the starting loads for a 150 grain bullet it says the minimum overall length should be 3.090 inches. I know that is a difference of 0.01, but looking at the 165 grain bullet reloading data it says the MOAL should be 3.105, which is a more substantial difference. To make matters more interesting I have some 180 grain factory loads which measure at 3.020 which seems to violate the MOAL rule of 3.090.

Ultimately my question is, why does the reloading data specify a minimum overall length greater than the maximum overall length? If the cartridge must be at minimum 3.090 inches then I will always be violating the maximum overall length.

 

[DW357]

OAL's can vary depending on the bullet type/shape/weight etc. as I think you realize.

The OAL's listed under the 150 gr data, isn't necessarily the "minimum" or "maximum" OAL to be used. They're not set rules where if you vary the length by 0.001" your gun will blow up. They're more of a suggestion based on the components and gun used by Lee when creating the load data.

The factory 180 rounds you have may not be (most likely not) the same 180 gr bullets that are listed in your Lee manual. So there is going to be some variation.

 

[cpuwhiz11]

Thanks for the response andrew1220. My followup question would be how do I go about figuring out what OAL I should be shooting for given the bullet type? Should I just try to get as close as I can to their minimum overall length?

 

[DW357]

Should I just try to get as close as I can to their minimum overall length?

That's what I would do. Just don't start at the maximum charge weight. Start at or near the minimum charge weight and work up from there checking for pressure signs and for accuracy etc. I'm not too familiar with the 30-40 krag cartridge and the rifles chambered in that caliber. I'm not sure if some 30-40 krag rifles have varying chamber/throat dimensions? @jpm and @NavelOfficer @mac1911 reload for these calibers if I recall correctly and can chime in.

 

[jpm]

So my pet accuracy load which is good in 3 or 4 different Krags from carbine to rifle is 37gr H4895 + 175gr Sierra Match king seated to 3.080" with a light crimp.

The max overall length they're talking about is the spec max length so it will fit in the magazine and feed properly. I would not sweat that because you'll most likely be seating deeper. The spec min is something like 2.96" so expect to be at less than that 3.089" pretty much always.

I just looked at the hodgdon data and they do list 3.090 for the 150gr. Give it a try, if it doesn't fit then you need to seat a little deeper.

 

[NavelOfficer]

You'll often find variations in load data from manual to manual and you may not find data for the exact bullet you are using. As stated above, your main parameters are does the round fit into the magazine well and does it chamber properly. This doesn't imply that you simply seat a bullet to any depth that functions, but don't be too miffed by a .0005" to .0010" discrepancy.
You will also find that some bullets don't measure up to spec when seated to the cannelure. It seems some bullet designs are caliber specific and the cannelure or crimp groove don't align in every similar diameter caliber. You can see where crimping will be inconsistent, if your brass lengths vary.
Although I've reloaded minimal .30-40 Krag, without the actual .30-40 Krag dies, I've simply neck-sized with other dies and made them work, but at some point I expect I'll need to full-length size the case with the proper dies.
SAAMI specs on page 97 or page 109/375...
https://saami.org/wp-content/uploads/2018/01/Z299-4_ANSI-SAAMI_CFR.pdf

 

[cpuwhiz11]

Ok, thanks everyone for the replies. For the specified minimum length jpm mentioned is that listed somewhere? I do not see it in the reloading data.

 

[jpm]

Reloading Data .30-40 Krag (Accurate Loading Guide #2) Metallic

 

[NavelOfficer]

Again...
https://saami.org/wp-content/uploads/2018/01/Z299-4_ANSI-SAAMI_CFR.pdf

 

[mac1911]

Only thing i have to offer is I/we used the data from the lyman cast bullet book. i would have to find the book to toss some numbers.

If your looking to see what the max length your rifle actuwlly can take . Seat a bullet very long and see if it will chamber.
Keep serting the bullet back say by .005" or so until your cartridge will chamber. Then consider the platform. I/we loaded for a rolling block.
Also note that load data is different for some older rifles and say a ruger #1.

If your loading in a magazine you need to run a COAL that functions in the mag.

 

[cpuwhiz11]

Ok, thanks everyone.

 

[gerrycaruso]

What rifle are you loading for? My son has a Winchester 1895 and I have a bolt action Krag carbine. The Krag seems to function better with a long C.O.L. That weird rotary magazine doesn't like bullets that have to make a long jump to the chamber. If you're loading for a Krag, keep the loads mild. The action is very smooth but besides being very old, it's not a very strong action.

 

[jpm]

Krag action isn't very strong because it only uses 1 locking lug, not because its old. That's probably also why its so smooth, but yeah don't try loading anything hot for it.

 

[gerrycaruso]

I didn't say the Krag is weak because it's old. I said it's old AND not very strong.

 

[5Red4White]

I find load data for a Krag 1898 using IMR 4831 resulting in respectable muzzle velocity but very low-end CUP using a 180-gr Hornady Interlock RN bullet (I don't want to go so light on bullet weight as 150-gr, but don't want to go so high on charge so as to push a 220-gr bullet with high pressure.

Anyone have experience with this combo?