I'm getting miss fires in a 45-70 using 40grns of IMR3031 and large rifle primes. The primer will push a column of powder and the bullet into the rifling.
Factory loads work great, this is my first hand loading the 45-70.

Any ideas?

First of all the minimum load of IMR3031 for a Marlin or Ruger with a 300gr bullet is approx 50 grs. What gun are you shooting it in and what bullet are you using?

I dont use 3031 in 45-70 but 1895ss does maybe he has suggestions.Is 40 grains below published loads? Do you have a good crimp? I would suggest if not, crimp your loads and switch to a magnum primer.I use Reloder 7 in 45-70 and never had any problems with a standard primer.

I have never had any missfires using IMR3031 in my 45-70. I don't use mag primers but I load approx 16 more grains of powder in my reloads then Badshot does. Then again approx 40 grs IMR3031 is minimum load in a trap door so maybe Badshot, you have contaminated primers.

The primer sounds to me like it is working if it has enough force to push propellant and bullet forward. If 40 grains is indeed a published load for3031 I would be inclined to believe that it may be related to bullet not held securely in place upon firing. I played around quite a bit with ammunition in my youth(one such experiment landed me in the emergency room,but thats another story) and found that if not enough resistance upon primer detonation the primer will just blow propellant forward without igniting it.I have removed the shot charge from a shotshell in an attempt to make a blank,guess what,without the pellets and crimps resistance the primer just pushes the powder and wad forward without igniting powder.I have had similar experiences shooting rubber BBs out of 22 rimfire.I would pull the lead bullet and replace it with a rubber BB used in toys.Same thing,the primeing mixture would not ignite the factory powder with the lower resistance of the rubber BB.To get this to work I had to dump the .22s powder and replace it with 3f black powder. I would take a hard look at your crimp and to echo 1895ss question what bullet are you using?

roklok could be right about the crimp or lack of it. We need to know more about this load and/or the loading process.

Welcome to the Forum! Sorry to hear about the load problem. These guys are good and will fix you right up. I would check the powder and maybe change primers. Something sure does not sound right. All the best...
Gil

Could also be case lube in the case contaminating the powder

40 grains of powder is rather low. 300 & 405 grain bullets need about 54 grains of IMR3031. Give us more info about primer, bullet weight, age of powder (any odor?) and type of gun you are using.
Keep it coming...

Badshot, welcome to the Forums mate. Sit a while and soak up the ambience. Roklok and 1895ss are both very experienced 45-70 shooters so these guys will get you on the straight and narrow......even if a Marlin is involved.

I am not a 45-70 shooter, but I am an experienced reloader so I am looking at it from a slightly different angle to the others. You say that "this is my first hand loading the 45-70".....does this mean that this is you first time reloading or just the first time for the 45-70? If it is your first time reloading I would suggest that you need to have an experienced reloader have a look at your set up and your procedures. If you have done a bit of reloading before then I would have a look at the set up of your reloading dies and the rest of your reloading setup. The problem may lie there.

Just a little food for thought.

Cheers, Vince

I'm going to commit myself and go with contaminated powder. I have never loaded for the .45-70, but I have never had a failure to fire with loose bullets in any calibre. I have shot .22's with loose bullets and have always had a problem with .38 Special having loose bullets, but no failure to fire because of it. IMR3031 is mid way down the burn chart and shouldn't be too hard to ignite. If it is contaminated powder or loose bullets, magnum primers will not solve the problem anyway. Now watch. after making that brash statement it will be loose bullets as the culprit...

I'm with you Bushy, I don't think it's a loose bullet problem. If the case has gone through the resizer die, then the case mouth should hold the bullet enough to ignite the powder. I too feel it's powder related, and when Badshot said he loaded 40 grains of IMR 3031, I got to thinking how does he know it was 40. Could be his scale isn't calibrated.

We need more info Badshot, so get in here & tell us more.
Keep it coming...

Thanks for the input and here is some of the info I should have posed in the frist place.
It a Sharps Trap Door. Wanted to keep the pressure low so that's why I went with the 40 grn of 3031 which should give me around 1200Fps.
Powder is a new can and smells okay. Primers are CCI 200. Case are new Remingtion.
I used a hand set of dies, and spray lube on the case, but they set for about two week before I actually finished loading them.

I think I'm leaning towards the lack of crimp.

I have been reloading for about 45 years, with no problems (bar some blown primers in 25-08 ACK, but thats a different story. My 5 yr old grandson, under pops supervision, reloads all my 223, 9 and 45. His only issue he complains that I shoot it all up and I won't save any for him until he get old enough to shoot).

Again thanks for all the input.

5 years old? And grandpa hasn't started him on a .22 rifle yet? What's the hold up?

Please let us know what you find out. We are a curious bunch.

My Hornady manual states that a trapdoor load of 40.9 grains of IMR 3031 is minimum charge with a velocity of about 1300 fps. What bullet are you using and did you crimp the cases at all?