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enfield
11-04-2012, 07:14 AM
I dusted off the 93 marlin yesterday and tried a couple new loads I found mentioned a more than once on here. 16gr 2400 and 18 gr 5744. both with the Lee 250gr booltit. after getting on paper at 25y I moved to 50 y and the groups were terrible, :-( at least 3 - 4 +inches. at the same time I would shoot my standard load of 6.8 gr trailboss with the same boolit & lube and 3 shots were touching .5 " group. the other thing I noticed was that the 2400 & 5744 had a lot more recoil but were hitting a few inches lower at 50 y. I expected them to be higher than the lighter feeling load of trailboss. my question is, could the bevel based Lee boolit be the problem with more stout charges of powder ?:veryconfu . the IMR book shows 7 gr trailboss giving 911 fps.

Nobade
11-04-2012, 09:23 AM
Depending on the groove diameter of your rifle, the Trailboss load may be bumping the boolit to fill the grooves where the 2400 and 5744 loads aren't, despite being a lot faster. Trailboss hits the boolit almost as fast as black powder and is one, if not the only, smokeless powder that will do this.

Hitting lower for faster loads is normal. Less barrel time, less recoil before the boolit leaves the muzzle. Happens more or less depending on lots of factors including stock geometry of the rifle.

You know that rifle will likely shoot its best with black powder, right? That is really what it's made and dimensioned for.

fouronesix
11-04-2012, 09:30 AM
It looks like the bullet- rifle combination likes a lower velocity/faster powder load for accuracy. Your 2400 and 5744 loads should be quite a bit faster than the Trailboss load- at least 300 fps faster according to my chronograph work with the 38-55. It's normal for lower velocity loads to print higher on target at shorter ranges. The muzzle has more time to rise while the bullet is still in the barrel with the lower velocity load. At longer ranges, you will start to see gravity take over and the lower velocity loads will start printing lower than the higher velocity loads. This phenomenon is especially noticeable with handguns. Oops, Nobade just hit the button faster :)

fouronesix
11-04-2012, 04:47 PM
So there's no confusion between your OP and bigted's post on the same rifle/cartridge. And this won't affect reported velocities nor pressures much if any, but I'm using a 250 gr gas checked bullet in my 38-55s. The plain base bullets are the design of choice for using blackpopwder and maybe even very light, low velocity charges of fast pistol powders like Trailboss or even Unique for the 900-1000 fps range. However, for consistent accuracy when using powders like Reloader 7 and 5744 for loads that give about 1250 fps (roughly original BP type ballistics), I found the gas check bullet along with dacron filler was the only way. I had all kinds of issues with accuracy and stabilization getting to roughly BP ballistics of 1250 fps with smokeless powder and plain base bullets.

KirkD
11-04-2012, 09:42 PM
Trailboss is a very fast powder and gives a very sharp pressure spike, so like Nobade said, it is probably bumping up the bullet. For the same bullet and velocity as original black powder loadings, however, Trailboss will give a much higher pressure spike than black powder. Trailboss is a great powder for reduced velocity loads that have a very high case capacity, exactly as you are doing. The other thing you might try if you want normal black powder velocities (around 1,300 fps with a 255 grain bullet) but with smokeless powder, is to use a softer-cast bullet, made from pure wheel weights. Don't water drop them. Just let them cool in the air. A lot of commercial cast bullets are hard cast and, thus, almost impossible to 'bump up'.

enfield
11-05-2012, 10:14 PM
some good points there, I will try some pure lead boolits for fun and I already did a little reaming of the bevel base mould so I will see if that helps too. as far as black powder , the bore is a little on the pitted side and I anticipate a pain in the butt cleaning ( I'm spoiled by the rolling blocks straight through with the boiling water and cleaning rod from the breach ).

Jon K
11-06-2012, 10:17 AM
Slug the bore, and fit the boolit to the barrel.

Fit is everything!

5744 loads are a bit light.

Jon

fouronesix
11-06-2012, 02:41 PM
Stating that simply sizing the bullet to the bore sure sounds good on paper, but in reality doesn't always work.

At least with original Winchester chambers (not sure about Marlin 93 chambers), fitting the sized bullet to the bore (do you mean groove?), much less .001-.002" larger than groove almost always causes a big problem! It is chronic with many original 38-55s. If that happens the best you can do is get cases with the thinnest neck walls possible then size the bullet so the loaded round chambers. Or if you want to mess around with an original gun, the only other solution is to ream the chamber to a slightly larger (.002" +/-) size.

"5744 loads are a bit light" ???? Well, my chronographed data shows 18 gr 5744 under that bullet yields 1200-1300 fps. There is nothing light about that compared to original 38-55 specs. The 6.8 gr Trailboss load IS light yielding about 900 fps. But, with the plain base bullet that may be the most accurate. I'd bet if you increase that Trailboss load too much the accuracy will go away, pressure may get spiky, more leading will be seen and accuracy will suffer.

Jon K
11-06-2012, 09:02 PM
Stating that simply sizing the bullet to the bore sure sounds good on paper, but in reality doesn't always work.
It works, if you are willing to do whatever is needed.

At least with original Winchester chambers (not sure about Marlin 93 chambers), fitting the sized bullet to the bore (do you mean groove?), much less .001-.002" larger than groove almost always causes a big problem!
It doesn't cause a problem, the problem was alredy there.

It is chronic with many original 38-55s. If that happens the best you can do is get cases with the thinnest neck walls possible then size the bullet so the loaded round chambers. Or if you want to mess around with an original gun, the only other solution is to ream the chamber to a slightly larger (.002" +/-) size.
Yes, those can resolve the problem, or reline the barrel, is another option.

"5744 loads are a bit light" ???? Well, my chronographed data shows 18 gr 5744 under that bullet yields 1200-1300 fps. There is nothing light about that compared to original 38-55 specs.
My chronograph print out only reads 1220fps w/19gr 5744, or 18gr 4759. Avg speed gain is 60 fps/grain. My chrongraph work was in 1893 Marlin(1901mfg), 1881 Marlin(reline), 2ea-1894 Winchester(1980mfg).



So, the question is "What are you willing to do, to make it shoot?", or Do you make it a "Safe Queen" or hang it on the wall?
I was willing to do all of the above, because a rifle that won't shoot to it's potential, to me is USELESS, but that's my decision.

Jon