Marlin responds

[44man]

Marlin sent me a letter telling why they use the 1 in 38" twist in the .44. They said ballisticians worked it out mathematically to determine the rpm's needed to stabilize a .44 bullet. They considered bullet center of gravity, length and diameter.
Seems as if all they used were 210 and 240 gr bullets.
They show a 240 gr at 1760 fps from the rifle doing a spin rate of 555 revolutions per second.
Then they show the same bullet from a 4", 1 in 20" revolver doing 708 revolutions per second.
Even at 1760 fps they can't match the 4" revolver.
We all know it isn't working.
My question to all of you is why does the 240 gr go wild when speeded up? I can only shoot light loads with accuracy, hunting loads spray the backstop at 100 yd's. Is it overspun? I never tried the 310 gr with a light load so what would happen if slowed down?
I am at the point where I don't know if the boolit is under or over stabilized.
They made the .41 with a 1 in 20" and those with other .44 guns claim 1 in 26" works best.
I am going to chronograph my most accurate light load to see what it is doing, also the heavy load that sprays the backstop.

[felix]

The lands are not gripping the heavier boolit is the only answer I can think of when the heavy boolit shoots at a lower speed. See if a stroked barrel per shot will shoot a group. Oiled, and then dried per shot, for example. If that works, then the lube viscosity must be dropped considerably, or shot when the barrel is hot to the touch with a heavier lube. ... felix

[Bass Ackward]

My question to all of you is why does the 240 gr go wild when speeded up? I can only shoot light loads with accuracy, hunting loads spray the backstop at 100 yd's. Is it overspun? I never tried the 310 gr with a light load so what would happen if slowed down?
I am at the point where I don't know if the boolit is under or over stabilized.
They made the .41 with a 1 in 20" and those with other .44 guns claim 1 in 26" works best.
I am going to chronograph my most accurate light load to see what it is doing, also the heavy load that sprays the backstop.


44,

Can't help an experienced reloader unless you understand his definitions.

1. What is accuracy and inaccuracy?

2. What velocity do you consider a hunting load? This may sound stupid, but if 1200fps is a handgun hunting load, then anything 1200 fps and over qualifies as trajectory enhancement by mine. Does this definition of mine alter the definitions in #1 above?

3. What bullet types are you using and are you staying at your usual hardness?

[mooman76]

I agree with felix totally in fact that is what I was going to say. Have you tried a harder bullet in your heavy loads or maybe .001 bigger? I assume you are using cast bullets. If you slow it down your accuracy should pick up. I have heard people say and I agree that you cannot over stablize a bullet. You can however put too much twist or over correct the stability where it jumps the lands like in your case!

[felix]

Moon, you can over-twist a projectile, because in practice a projectile has to be in perfect balance to fit that rule about over-twisting. Besides, lead boolits will tend to come apart even if they were in perfect balance to begin with immediately out of the barrel. We should try and stay below 150K rpm... felix

[44man]

OK, lets see if I can go through it. This rifle has Ballard rifling, the bore is .4296", I shot .430, .431 and .432 boolits. My Hoch spitzer and an RCBS 245 gr shoots fantasic with 6.5 gr's of 231 or 7 gr's of Unique, making a ragged hole at 50 yd's and still good at 100 but with a tremendous drop. If I speed these boolits up with 296 or any slower powder, anywhere from minimum to max, were are talking a one to two foot pattern at 100 yd's. The Lee 310 only shoots half decent with 21.5 gr's of 296 but not all the time. Any change starts to scatter groups but I have not tried real light loads with a fast powder with the heavy boolit.
I use Felix lube and Lar's carnauba red with no change. I get no lead in the bore. I have shot it hot and cold and clean. I have floated the forearm and there is no front band, the tube floats. I even power lapped the bore.
I have tried my alloy which is hard, air cooled and water dropped WW and 50-50 WW and pure. Babore sent me a bunch of different boolits of several hardnesses to try and they also shoot the same way.
The results are the same across the board, if I speed it up it goes to pot in a hurry. I don't know what the velocity is with 7 gr's of Unique but it can't be that high, less then 1000 fps, maybe way less.
This rifle should shoot good to 1800 fps.
I have one more thing to do and that is a scope change to see what happens. I also have to haul down the chrono.
Then the unthinkable--a jacketed bullet! [smilie=1:

[BABore]

Have you checked the throat dimensions? Also the diameter of a fired case that was from a stout load. You may have some oversize issues that show up more when you really kick the bullet in the pants. Try to recover some HV bullets from a soft media and see what the engraving looks like at the bullet's base. A jacketed bullet will overcome most of these issues and conceal the root cause. Might need to do a chamber/throat cast or impact casting to see what's going on.

[Bass Ackward]

OK, lets see if I can go through it. This rifle has Ballard rifling, the bore is .4296", I shot .430, .431 and .432 boolits. My Hoch spitzer and an RCBS 245 gr shoots fantasic with 6.5 gr's of 231 or 7 gr's of Unique, making a ragged hole at 50 yd's and still good at 100 but with a tremendous drop. If I speed these boolits up with 296 or any slower powder, anywhere from minimum to max, were are talking a one to two foot pattern at 100 yd's. The Lee 310 only shoots half decent with 21.5 gr's of 296 but not all the time. Any change starts to scatter groups but I have not tried real light loads with a fast powder with the heavy boolit.
I use Felix lube and Lar's carnauba red with no change. I get no lead in the bore. I have shot it hot and cold and clean. I have floated the forearm and there is no front band, the tube floats. I even power lapped the bore.
I have tried my alloy which is hard, air cooled and water dropped WW and 50-50 WW and pure. Babore sent me a bunch of different boolits of several hardnesses to try and they also shoot the same way.
The results are the same across the board, if I speed it up it goes to pot in a hurry. I don't know what the velocity is with 7 gr's of Unique but it can't be that high, less then 1000 fps, maybe way less.
This rifle should shoot good to 1800 fps.
I have one more thing to do and that is a scope change to see what happens. I also have to haul down the chrono.
Then the unthinkable--a jacketed bullet! [smilie=1:


44,

I doubt that it's scope. But you can try that. My grandmother always said, "Person never knows". If that isn't it, trying it will serve to reinforce this lesson that Professor Gun is teaching though. :grin:

Felix is correct that you may see a difference but I doubt to your satisfaction. I mean that you aren't battling 6" groups here wanting 4", but total losers, unless you are shooting gallery type stuff that doesn't cause a lot of vibration. :grin:

If this was me I would have fire lapped awhile ago. It's mostly finish, not dimension or you would be leading. So I would suggest a Tubb's kit. No sense lengthening the throat. A Tubb's kit is about like 400 jacketed bullets without all the cost. Or 2500 lead ones. Reminds me of that Miller commercial, If you got the time ...... I .... got .... the .... beer.

[44man]

I did more work today and shot the 240 XTP's at 50 yd's. Best I could get is 2-1/2". I also changed the scope.
I MADE A MISTAKE--I grabbed the wrong slug on the bench, my groove to groove is .430".
My barrel is also only 16" so I will not get the high velocities.
Now here is the kicker, I measured the bore and it is .424", THE RIFLING IS ONLY .003" DEEP! :???: My SBH is .0065". Marlin has not increased the rifling depth with the Ballard rifling over the micro groove, so what good is it?????? In fact it can be worse with less gripping surface. I am shooting close to a smooth bore. No wonder I can't spin up a boolit, they need to be super hard or super slow to get a bite on the rifling.
Now here is a quote from Ken Waters pet loads book concerning the Browning B92;
"It's demonstrated accuracy does not equal it's fine appearance, mainly because of it's shallow, too slow 38" twist rifling. If the Browning were rebarreled with a 20" twist like the Redhawk's, I'll wager that it's shooting would match it's looks."

It looks like I would have to spend big bucks to get it rebarreled before I can expect anything from it.

[45 2.1]

I did more work today and shot the 240 XTP's at 50 yd's. Best I could get is 2-1/2". I also changed the scope.
I MADE A MISTAKE--I grabbed the wrong slug on the bench, my groove to groove is .430".
My barrel is also only 16" so I will not get the high velocities.
Now here is the kicker, I measured the bore and it is .424", THE RIFLING IS ONLY .003" DEEP! :???: My SBH is .0065". Marlin has not increased the rifling depth with the Ballard rifling over the micro groove, so what good is it?????? In fact it can be worse with less gripping surface. I am shooting close to a smooth bore. No wonder I can't spin up a boolit, they need to be super hard or super slow to get a bite on the rifling.
Now here is a quote from Ken Waters pet loads book concerning the Browning B92;
"It's demonstrated accuracy does not equal it's fine appearance, mainly because of it's shallow, too slow 38" twist rifling. If the Browning were rebarreled with a 20" twist like the Redhawk's, I'll wager that it's shooting would match it's looks."

It looks like I would have to spend big bucks to get it rebarreled before I can expect anything from it.

You do have an option here. Make yourself a 225 to 230 RF mold at 0.423" as cast with 8 BHN boolits. That slug will need a series of light lube type grooves about 0.010" deep with a taper crimp groove at the correct location. Paper patch those with 0.002" paper down the ogive some and they will shoot out of that rifle at about any velocity you can muster with accuracy.

[44man]

I might just have to try that. I also checked the Ruger site and their lever guns are 1 in 20 but I don't like the rotary magazine that won't hold much in the way of boolits.

[Lloyd Smale]

sent you a pm.

[Bass Ackward]

Now here is a quote from Ken Waters pet loads book concerning the Browning B92;
"It's demonstrated accuracy does not equal it's fine appearance, mainly because of it's shallow, too slow 38" twist rifling. If the Browning were rebarreled with a 20" twist like the Redhawk's, I'll wager that it's shooting would match it's looks."

It looks like I would have to spend big bucks to get it rebarreled before I can expect anything from it.


44,

My rifling height in my Ballard is .0027. It hold 1" with ACWW with several designs and sometimes MUCH better :grin:

Want to know what's funny? This was probably the smoothest bore I ever saw. But it wouldn't shoot for crap, so I lapped it. :grin: Nuff said.

And Mr Watters has a different Browning than I do. My groove is 429 and the bore is .421. That's 12 rifling that are .004 tall. We have two and these shoot very well with 265 grains and below.

[44man]

Bass, I did lap it, you missed it in my earlier post. :coffee:

[454PB]

I take the easy way out on all my Marlins.....I use gas checks!

[Bass Ackward]

Bass, I did lap it, you missed it in my earlier post. :coffee:


44,

Sorry, I apologize. Missed it entirely. Goes to prove that bore finish and dimensions are only two pieces of the puzzle. Then Bob's answer is your only hope. You want to try anything from me ask off line. I have several customs, but I don't have any miracle workers for 1 1/2 feet to 1". :grin: If jacketed won't do it, lube change or hardness increase, or bullet design probably won't do "enough" either.

Lapping is the last resort for most people. Me, I am a little backward and I do it right off and do the jacketed test right off. Especialy with the Tubbs stuff available now. No more than .0003 metal is a willing sacrifice. That set's the standard to tell me if it's worth my time. If it won't work there, or is finicky, then it definitely is a cast component waster. Some people like challenges. Me too, if it's a handgun or that was from the 1800s or something, but not in that rifle for me.

Ain't twist rate cause 38 twist, if anything needs to be pushed harder to stabilize and jacketed should work if rifling height WAS the issue. My guess now is that stress in the steel is causing everything to shift as it heats, but that could be proven with one shot every half hour.

Just so you know, your lapping probably didn't lower the rifling height if it's anything like mine, .0027 was the same before and after although the leade angle did change a good bit. Did wonders for mine as cast sets the standard on this one now. Wife wanted 240 XTPs for season though as she doesn't like 280 grain recoil. First load let me off the hook as it was 5 @ 1 3/4" which she burned right off in half a minute and made her happy enough. Few water jugs around her stand for confidence and she'll be a killer. :grin:

[44man]

I do use gas checks except on some of the test boolits that were sent for me to try. What burns me is once in a while I shoot a nice tight group at 100 with a flyer ruining it and the next time I shoot the same load it goes all over the place. No rhyme or reason.
When I took the 245 boolit up to a hunting load, away from the cowboy stuff, I sprayed the whole backstop and poked holes all over my steel target holder. I would not hit a moose! :roll:
I am going to gather a bunch of water jugs and try to catch some boolits.

[44man]

I tried a bunch more boolits and loads yesterday and the 432-310 PB that Babore sent me shot good but the hollow point of the same boolit was not as good. For some reason I was getting sticky cases with the hollow point that weighs around 285 gr's even though I used the same load with the 310 with no problems.
I went back to the Lee 310, 21.5 gr's of 296, fed 150 primer and sighted the gun at 50 yd's. It came right in and hit good at 100 yd's too. That has been the best load for the gun from the start and is the only one that shoots good enough to hunt with. I seat and crimp in the lower crimp groove.
I will now set it aside, can't do any better.

[TedH]

I tried a bunch more boolits and loads yesterday and the 432-310 PB that Babore sent me shot good but the hollow point of the same boolit was not as good. For some reason I was getting sticky cases with the hollow point that weighs around 285 gr's even though I used the same load with the 310 with no problems.
I went back to the Lee 310, 21.5 gr's of 296, fed 150 primer and sighted the gun at 50 yd's. It came right in and hit good at 100 yd's too. That has been the best load for the gun from the start and is the only one that shoots good enough to hunt with. I seat and crimp in the lower crimp groove.
I will now set it aside, can't do any better.


That's the exact same load I ended up with in my Marlin. It made a big difference in accuracy crimping in the bottom groove instead of the top one.

[Bass Ackward]

Been thinkin. It still sounds like you have a rough bore issue even though you lapped. After you lapped did you break it in again? Sometimes you have to cause you open the pores in the metal. You'll know in awhile if this was the problem. Example.

We did our 35s last spring. These rifles were as close as can be. Barrels ordered / delivered the same time, cut back to back with the same reamer, etc. Both fired one kit. Mine went right back and after, it digested lead just like it did before with a 50 fps increase. Dad's threw more pressure with his loads from before and was almost 2". No leading, just change. After cussing, he took the shoot clean, shoot clean routine for 10 shots with copper and almost 40 lead squibbers later and now pressures and accuracy back to where it was as far as finish goes with those same loads. He hasn't investigated to see if his ceiling raised any. So one did, one didn't and they are sisters. My guess here is that his bore was tighter than mine and just roughed up more. But who knows?

This is why lapping is misunderstood so badly. You can't always pick back up and think you are comparing apples to apples. That's where the Tubb's kit shine. A worn jacketed barrel goes down to like 3400 - 4200 microns in the finish depending on the steel and how much pressure is behind that. More pressure works faster. But in a cartridge like a 44, the copper is thin and the bullets soft and you just don't generate that much pressure. And with the 38 twist, you ain't running the RPMs either.

The Tubb kit's use aluminum for the cutting and stay fairly close to that level compared to the grits. Still a break in will show improvement under most situations if the barrel diameter is still tight for the rounds. Sounds like a description for cast doesn't it? Have you tried any .429 Speer's in that? You said your finished diameter is .430. Say about 23.5 grains of 296 should tell ya. That works in many situations.

Or if you don't have any, you sould have some RL7. Try about 20 -21 grains with the 310 Lee seated out and see if you burn it and what happens. Remeber, start low and come up. I really think it's pressure and maybe why you got the hollow point results you did too. If the RL7 does better then you'll know what you have to do.

[44man]

I did use up the last of my jacketed bullets for a break in, just didn't have enough. It is shooting OK with the one load and since it is the grandsons gun for deer, it will do the job now.
The only strange thing is the heavy boolit had no pressure signs and cases fell out but the lighter hollow point of the same boolit gave me a few sticky cases. I shot them last and I think I was getting a build up of boolit lube in the chamber. I cleaned the gun and ran all of the cleaned empties through it and none were tight. It was just crud! I didn't take a rod down to the range.
It has a tight chamber and loads for my SBH will not fit in the gun since I neck size only. I have to keep brass separate.

[longbow]

Another thing you might check is if there are any tight spots in the bore. I was having trouble with my Marlin 1894 .44 mag with 1:38 twist microgroove mainly with heavy boolits over 265 gr. (0.72" long) and at ranges over 50 yards. After failing miserably with those I went back to 240 to 265 gr. and still couldn't get decent accuracy where I had before! Used to get good groups at 100 yards with 240 or 265 gr.

I decided to thoroughly clean and check the gun and found that the bore had leaded very thin and even like a thin layer of solder that was hard to remove. Now I had cleaned after every time out including a few passes with a bronze brush but this leading was so thin I couldn't see it and it didn't come out with the bronze brush. A really tight jag with a patch picked up some flakes so I knew there was a problem and worked on it until I got it all out.

Afterwards I found some comments on the Marlinowners forum about Marlins being particularly bad for tight spots at the dovetails so checked mine. Sure enough a tight spot at each one. I was reluctant to lap with microgroove rifling because the isn't much to lap but decided if it didn't work I would just get it rebarreled.

I made a lap and hand lapped taking a little more time at the tight spots until it smoothed out.

Prior to lapping I had found some loads did not too bad for accuracy but most boolits I recovered showed signs of gas cutting on the base and sometimes a ways up the sides. A particular offender is a Lyman 429421 mould that I despise for many reasons. Largely it is over length for the unmodified Marlin so I have to crimp over the front driving band but due to the silly ass shoulder of the semi wadcutter it still doesn't feed well - hangs up up on the chamber mouth. To top it off it is a mediocre to poor shooter with any load at any range. I find that round nose flat point feed and shoot well.

Anyway, I never really had a problem with leading prior to the heavy boolit tests so I'm thinking that hot loads and high pressures produced the solder like leading. Once that leading was established my accuracy with all boolits deteriorated.

After lapping I see better accuracy, little if any gas cutting and no leading. I have to conclude that the tight spots were swaging the boolits down and allowing blowby resulting in gas cutting and leading. It still doesn't like boolits over about 0.75" long but is doing well with up to 265 gr.

All boolits shot were ACWW and at or slightly above groove diameter.

The short story is - slug your bore to make sure your boolits are a good fit and check for tight spots. The lapping you have done may have removed them if they were there but it wouldn't hurt to check. Hand lapping allows you to feel if and where any tight spots are.

[Mayor]

Have you examined (closely) the barrel crown?
Might be worth scrutinizing at this point.