45-70 won't group

jdschwass

jdschwass

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Heyall,

I am experiencing some great frustration here, and decided it’s finally time to reach out. I’ll try and be as detailed as possible.

A couple years ago I purchased a Marlin lever action in 45-70. (new) I casted a pile of bullets from the Lee 405 gr mold, which I then tumble lubed with Lee Liquid Alox. I did not size the bullets.

I did some ladder testing with 4198, and settled on a load around 46gr, which was getting me about 1.5 inch groups at 50 yards off the seat of a snowmobile. Good enough for me.
I then loaded up a full box of 50 rounds of that load.

About 6 months ago I was out at the range and I found that the shots were walking on me, and realized that my scope was sliding through the rings. After mitigating the scope issue, I loaded up another box of 50 rounds.

I was out shooting over the last couple weeks, and I cannot get this thing to group. I am seeing flyers all over the place, the best groups I can get ignoring the flyers is about 2 or 3 inches at 50 yards of a bench rest.

I guess my questions are… what kind of accuracy should I expect from this rifle? What could be causing this erratic shooting? Is there a different load that I should be trying?

This gun is primarily my bear hunting rifle, so shots between 50 and 150 yards would my useful range, which currently I cannot trust to make.
The only other thought I had was to buy some bullets and eliminate the casting from the equation, but I find it hard to believe I would see groups like this because of tiny variations in bullet weight.


Thanks for any advice.
 
reb said:
A good cleaning, Are you using a gas check on your cast bullets.
Click to expand...
I agree. Don't know how fast you're pushin em, but I use gas chks on my 45/70's and 38/55's and get great accuracy. Just a thought, I'm learnin every day. When I was 30, I thought I knew everything, now I know I have a lot to still learn.
 
That is a super fast load for a plain based cast bullet. I would be shocked if it didn't lead the bore. Sometimes you won't find the lead until you push a few very tight patches ( on a jag ) through the bore.

I've owned a number of Marlin .45-70's and they were all a lot more accurate than you would expect. I think 1.5-2" 5 shot groups at 100m is about average for a good cast bullet load or a jacketed one.

Chris.
 
Damn, 2 MOA would be great...
I appreciate all the advice. I'm going to clean the heck out of the barrel for starters. That could explain why the load started off accurate and opened up over time. It's entirely possible I missed the leading. Normally I would see strands of lead if they are running too quick.
I dont really want to check my bullets, I would be more inclined to slow things down. I will explore some different loads.
I'm feeling a bit better about it now, thanks again. If it's just my own doing, I'm okay with it.
Cheers
 
Clean your barrel really well, my 45/70 would lead foul and the groups went all over.
I found that around 1800fps with a 405gr lead was right in the ballpark for a load that didn't kill your shoulder and was fairly accurate.
You don't need to push a 405gr really fast for it to do it's job so I don't think you need to load hot just because it's for bear.
 
Sounds good. It's a good excuse to try some new loads anyways. I have read a lot of good things about 3031, I might try that. My 4198 supply is almost spent. I just want a lead free load that can hit the boiler room at 150 or less. I dont care to dislocate my shoulder in the process. My current loads are pretty stiff!
 
It's now on the top of my list of things to do. But I would like to find a load that doesnt lead up. I appreciate the feedback though guys, it's amazing how a pain in the arse can be such a simple fix.
 
The recoil could be part of the issue for less than acceptable groups too, as over time shooting a heaving recoiling gun like a 45/70 you will develop a flinch and your accuracy will suffer because of it.
 
From past experience, 46gr of 4198, either, is probably too warm for plain base cast alox bullets. Gas checks or possibly powder coating will very likely remedy this. Also, depending on alloy and if you water quench or not, the bullet might come out a couple thou small.

When I started shooting cast, my rifle came with a 250 box of bullet barn 350gr hard cast plain base. I shot some out at 1500 or so and in trying to get the rifle to shoot and learning it in general, I basically turned it into a smooth bore. Took hours to clean that out and learned my lesson.
 
OP, you're alloy is probably at fault. Not hard enuf & no gas checks = a leaded barrel.
I've had leading start in revolver barrels as low as 1050fps with wheelweights.
Harden up your mix and gas check them.
 
Heyall, first off, I have to apologize because I mixed up some loads in my head, and my original post was incorrect. During my initial ladder testing when I got my Marlin, I performed ladder testing with IMR4198 from 36 to 40 grains in one grain increments. (I did not load 46 grains). This was performed with a 405 gr. cast bullet. The data I used was from the Lyman 49th, which should be right in spec for a plain based cast bullet. The best accuracy I got during this testing was with 38gr of powder, so I should be in the middle of the road for pressure.
Sincere apologies for the incorrect data.

All that being said, I did a cleaning of the bore this afternoon. There was some leading present, but not near as bad as I have seen with other guns. Having done more research, some people see fantastic accuracy with this cartridge, I feel I should be able to do better.
I could load up some more of the same and hope the clean bore makes a difference... otherwise....??? I am temped now to pick up a bag of jacketed bullets just to rule out my casting.
I dont think my alloy is to blame. I cast with water quenched wheel weights.

Thanks for getting me to clean my gun... I should do it more often. Otherwise I am still a bit unsure where to go from here. Fingers crossed all it took was a dirty bore.

Thanks,
 
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