44 mag micro groove leading throat only with .435" bullets

[LUTNIT]

Hello,

I know the micro groove barrel leading issue has been done to death but I ran into something new.

I'm using WW alloy, water dropping the bullets, and tumble lubing them with the Lee liquid alox.

I tried .430" 200gr plain base bullets before and they leaded the bore and occasionally tumbled. They dropped .431" as cast from a Lee mould. This is to be expected.

Lots of people/books/forums say to use .432" or even .433" cast to work well in MG rifled barrels so I moved up to an NOE .432" 200gr mould designed for .44-40. They drop .4345" to .4360" from the mould and I don't size them. They shoot accurately but leave very heavy leading in the first 1-2" of the barrel in front of the chamber. By heavy leading I mean it looks like 60-70% of the barrel surface is coated in lead. Normally in this same rifle with .431" bullets there are flakes of lead adhered to the barrel randomly along it's entire length; no where near this coverage.

My thought was that the bullets are too large and when swaging down into the throat they are leaving deposits? I haven't slugged the barrel but it's in excellent condition and I assumed .4315" as Marlin states.

Is the bullet now too large? Could this be fixed with a gas check bullet? I'm kind of stumped.

Thanks

*edit*
Forgot to add. I'm only pushing these .435" bullets at ~1100fps to get this result. I tried cranking them up to 1600fps but it got even worse.

[Char-Gar]

I would expect plain base, tumble lubed bullets to lead the barrel when fired from a 44 Magnum rifle. That is why I shoot gas check bullets with a good quality conventional lube in mine. I don't get any leading.

[LUTNIT]

Any reason why tumble lubing would increase leading? First I've heard of it.
I've also read many people reporting no leading with plain base bullets of at least .432" diameter.

[williamwaco]

You might need to experiment with this one.
I doubt If you are going to find anyone with first hand experience with bullets that large.

I doubt that sizing them down in the bore is causing the residue. Sizing them .006 in a sizing die does not leave any residue. Of course that is not really comparable to a whack of several thousand PSI.

You did not mention the load but I expect 1100 fps with WCWW bullets is not enough to obturate the .431 bullets and the bullet is too small and rattling down the bore like a marble.

My first test would be to size the larger bullets.
Since you already know .431 is too small, I would try .432, then .433

I would not water drop them.

I would not assume the .4315 that Marlin quotes is correct.

If that doesn't work try air cooled wheel weights sized .432 at 1600 fps

Then, get a gas check.

[Starrbow]

Get a Lee sizer in .432/.433 and be done with the leading! You can special order them from Lee, or get a off the shelf .430 and have a local machine shop open it up to .432/.433.

[LUTNIT]

Get a Lee sizer in .432/.433 and be done with the leading! You can special order them from Lee, or get a off the shelf .430 and have a local machine shop open it up to .432/.433.
That's what I was going to try next. I have a .430 that's doing me no good so I was going to ream it out to .432" and try again. If that failed I was going to go up to .433".
I was just wondering if anyone else had had these leading issues with such hugely oversized bullets before.

[hickstick_10]

Two things to ask, whats your bore slug at (you need to measure this not take marlins word for it) and what powder are you using?

You can push a plain base at that speed (1100 fps) no problem, but sooner or later you're going to want a lubesizer. Are you getting good accuracy and chronographing these loads?

[LUTNIT]

I didn't slug the bore but I'll cast some .438" round balls tomorrow to do so.
The powder I'm using is Unique. I also tried H110 but it didn't work so well.
Accuracy is fine with the .435" but was junk with the .431".

7gr gave 1117fps
9gr gave 1405fps
11gr gave 1630fps

Those are all 5 shot averages
7gr gave the best accuracy
9gr was mediocre accuracy
11gr was all over the place
All three leaded the barrel in the same way; the first 1-2" had a lot.

I also tried 24gr of H110 just to see if it worked for whatever reason. It chronied 1935fps and it left lead in the entire length of the barrel (normal amounts.)

Is there that big of a difference with a lubrisizer? I've got cast loads in other rifles/calibres shooting 2" at 100yds with tumble lubing and Lee push through sizing dies. If I just ream sizers I need that Lee doesn't offer will a lubrisizer really improve performance?

[RickinTN]

Your Lee die opened up gradually is a great way to experiment and find what the rifle likes. You already know that a .435" bullet will chamber, so that's no issue for .432 to .435. You can open the Lee sizer yourself with little effort. A power drill, a short section of 3/8" or so wooden dowel, some packing tape and some 320 or smaller wet or dry paper. Open it up about .001 at a time and try it.
If you wanted to try some conventional lubes you can accomplish this for much less money than a Lubesizer. I do own a Lubesizer, but recently in an effort to try different lubes I tried pan lubing and also dip lubing. Making a cake-cutter for either method should be easy enough with a fired case.
Good Luck,
Rick

[Keyston44]

I use the Ranch Dog 265gr tumble lubed mold that has 3 cavities gas checked and 3 plain base. I size them to .433 using a Lee 430 push through sizer I opened up to 433. Lube is 45-45-10 mix and I dip lube them. I don't have my notes with me to reference my fps but I'm almost sure the plain base are moving 1100fps and the gas checked are going 1600 without any leading.

Key

[1Shirt]

Mine shoots .431 plain base or gas checked without leading. I use White Lable/Can red lube.
1Shirt!

[hickstick_10]

I didn't slug the bore but I'll cast some .438" round balls tomorrow to do so.
The powder I'm using is Unique. I also tried H110 but it didn't work so well.
Accuracy is fine with the .435" but was junk with the .431".

7gr gave 1117fps
9gr gave 1405fps
11gr gave 1630fps

Those are all 5 shot averages
7gr gave the best accuracy
9gr was mediocre accuracy
11gr was all over the place
All three leaded the barrel in the same way; the first 1-2" had a lot.

I also tried 24gr of H110 just to see if it worked for whatever reason. It chronied 1935fps and it left lead in the entire length of the barrel (normal amounts.)

Is there that big of a difference with a lubrisizer? I've got cast loads in other rifles/calibres shooting 2" at 100yds with tumble lubing and Lee push through sizing dies. If I just ream sizers I need that Lee doesn't offer will a lubrisizer really improve performance?


Your trying to get alot of speed out of Unique (never was its strong suit) and out of a tumble lube. If you tried IMR-4227 you probably would have better luck with a lever gun.

There is a big difference with the lubesizer, namely the ability to put a decent lubricant in a grooved bullet. Alox is an excellent product as is their tumble lube moulds but they have always been a compromise and In my opinion not geared towards full house magnum loads.

[LUTNIT]

I know Unique is meant more for 44 spl and not 44 mag but that and H110 (which only seems to work well for magnum loads) are the only powders I have that I can find data for. I will go and try some others as soon as I can find them (damn powder shortage).

I reamed out my .430 sizer to .432 and sized some bullets. I am heading to the range tomorrow to give them a test. Until I get a gas check mould I'm limiting myself to 44 spl loads. Once I find a plain base size that doesn't cause leading for 44 spl I'm going to order a 240gr gas check mould from Accurate Moulds at .001" larger (just in case).

[jethunter]

That bullet is meant for low velocity 44 russian and 44 spl in the 800 fps range. There is only about 1/4 inch total bearing surface.

Maybe the bullet is slipping in the rifling for the first 1-2 inches because there isn't enough meat to hold a grip with 20,000 psi behind it. The pressure drops rapidly after the first 2 inches of travel and the bullet can grip the rifling without slipping from there on.

Maybe a bullet with larger bearing surface would work better.

[LUTNIT]

I was thinking that was a possible reason but figured if it was slipping there would be leading along the entire length. You could be right that once it starts accelerating at a slower rate it engages and runs fine, I dunno. It does seem odd that it leads the same section of the barrel even at 44 spl velocities though.

[jethunter]

Can I ask what your load of Unique is? Be fun to run it through Quickload and see what the peak pressure is and how fast it disipates.

[longbow]

Well, lots of advice already.

While this may not apply to your situation, I was having some serious leading issues with my Marlin so got to checking into why. First off I was using an undersize boolit Lyman 429421 that cast at 0.429" being shot form a 0.4315" groove diameter. So got a larger mould and that helped but did not solve it.

More searching came up with the fact that apparently it is common for Marlins to have tight spots in the barrel under dovetails and roll stamping. I slugged my barrel and ran the slug carefully through the barrel. Sure enough, I had several tight spots.

Some careful hand lapping fixed that and leading about disappeared and that is with all PB boolits and up to max loads of IMR4227 which is my go to powder for the Marlin.

Since yours is leading in the beginning of the barrel it may not be roll stamping or dovetails but it would be worth a check. You may have a tight spot just after the chamber.

I am thinking that at the relatively light loads and low velocities you are shooting that the leading is not due to pressure or boolit design.

I would slug the barrel end to end carefully to see if there is a tight spot. If not then move on to eliminate the next possibility but if so that may be your answer.

Longbow

[lonewelder]

wdww might be too hard for 7gr uni

[bones37]

My experience with my 80's vintage 1894 .44 mag with microgroove basically mirrors what Longbow has stated. The rifle was a safe queen when I got it, and further inspection confirmed that it hadn't been shot any, or very little at best. It slugged out .4315" ish, and I had a RCBS 200 CM mold enlarged to cast .433" with COWW. I also ordered a 43-250K from Accurate which also casts at .433". Obviously the 200 grain has a slight accuracy edge over the 250, but both are accurate enough for me.

The bore had rough spots and tight spots, which was causing some minor leading, so I also spent several hours hand lapping the bore with great results. I hope You figure out what is causing Your issue, they can be made to shoot without leading, it is just finding out what needs to be done. Bones.


Well, lots of advice already.

While this may not apply to your situation, I was having some serious leading issues with my Marlin so got to checking into why. First off I was using an undersize boolit Lyman 429421 that cast at 0.429" being shot form a 0.4315" groove diameter. So got a larger mould and that helped but did not solve it.

More searching came up with the fact that apparently it is common for Marlins to have tight spots in the barrel under dovetails and roll stamping. I slugged my barrel and ran the slug carefully through the barrel. Sure enough, I had several tight spots.

Some careful hand lapping fixed that and leading about disappeared and that is with all PB boolits and up to max loads of IMR4227 which is my go to powder for the Marlin.

Since yours is leading in the beginning of the barrel it may not be roll stamping or dovetails but it would be worth a check. You may have a tight spot just after the chamber.

I am thinking that at the relatively light loads and low velocities you are shooting that the leading is not due to pressure or boolit design.

I would slug the barrel end to end carefully to see if there is a tight spot. If not then move on to eliminate the next possibility but if so that may be your answer.

Longbow

[Grapeshot]

Hello,

I know the micro groove barrel leading issue has been done to death but I ran into something new.

I'm using WW alloy, water dropping the bullets, and tumble lubing them with the Lee liquid alox.

I tried .430" 200gr plain base bullets before and they leaded the bore and occasionally tumbled. They dropped .431" as cast from a Lee mould. This is to be expected.

Lots of people/books/forums say to use .432" or even .433" cast to work well in MG rifled barrels so I moved up to an NOE .432" 200gr mould designed for .44-40. They drop .4345" to .4360" from the mould and I don't size them. They shoot accurately but leave very heavy leading in the first 1-2" of the barrel in front of the chamber. By heavy leading I mean it looks like 60-70% of the barrel surface is coated in lead. Normally in this same rifle with .431" bullets there are flakes of lead adhered to the barrel randomly along it's entire length; no where near this coverage.

My thought was that the bullets are too large and when swaging down into the throat they are leaving deposits? I haven't slugged the barrel but it's in excellent condition and I assumed .4315" as Marlin states.

Is the bullet now too large? Could this be fixed with a gas check bullet? I'm kind of stumped.

Thanks

*edit*
Forgot to add. I'm only pushing these .435" bullets at ~1100fps to get this result. I tried cranking them up to 1600fps but it got even worse.

You might try using a 30-to-one Lead Tin alloy. Your bullets are to hard and do not obdurate properly to keep the hot gas behind the boolit.

[LeftyDon]

I know Unique is meant more for 44 spl and not 44 mag but that and H110 (which only seems to work well for magnum loads) are the only powders I have that I can find data for. I will go and try some others as soon as I can find them (damn powder shortage).

I reamed out my .430 sizer to .432 and sized some bullets. I am heading to the range tomorrow to give them a test. Until I get a gas check mould I'm limiting myself to 44 spl loads. Once I find a plain base size that doesn't cause leading for 44 spl I'm going to order a 240gr gas check mould from Accurate Moulds at .001" larger (just in case).

What other powders do you have? I've got some data for red dot/green dot and trail boss plus some others.

[longbow]

You shouldn't need a gas check if boolit size is good. I push mine to "J" bullet velocities in my Marlin now with no problems and all are plain base boolits.

I mainly use IMR4227 in the .44 mag because it gives good velocities (not as good as H110 though) and I use it in .303 and .308 as well.

I am normally shooting 240 to 270 gr. boolits form Mihec moulds ~ 434640 and H&G #503 clone (Keith SWC) both plain base. Lately I have been shooting quite a few 165 gr. TC boolits from Accurate Molds #43-165B. I haven't chrono'd them but 10 grs. 700X makes them scoot along pretty good and quite accurate so far.

I haven't sat down and really shot groups seriously to compare but so far the H&G #503 has given best groups of the three and all are shooting head and shoulders better than what I used to get with the Lyman 429421.

After lapping and fattening up the boolit diet, leading is a thing of the past for me.

Having said all that, a gas check is not a bad thing if you want one. It certainly won't hurt and may help accuracy and in reducing leading. I am just too lazy to make and install (and too cheap to buy them) so figured out a way to shoot the PB boolits that works for me.

Longbow

[6pt-sika]

Quit wasting your time with PB billets and use the Ranch Dog 432-240GC or 432-265GC then push them with H-110 and your problems will go away . In a couple Marlin 336-44 rifles of 1967 vintage I had excellent no leading results using the 240 grainer with 24 or 25 grains H-110 . With the 265 grainer I used 23 grains H-110 . And furthermore with the Ranch Dog 432-300GC I used 21 grains H-110 and all three were easily 1 1/2" for 3 shots at 100 yards . I realize there are alot of folks who would rather use PB bullets and that's good and fine but you're life may get alot easier if you go GC .

[6pt-sika]

Oh yeah I had good results using .430 and .431 bullets in those 336-44 rifles . But later when u went to a .432 die accuracy noticeably improved . At the time I also had a .433 die but never saw a need for it ! Now I use a .433 due exclusively for my 444's and if I ever cast for another 44 Mag I'll use the .433 for that as well .

[IridiumRed]

I'm gonna go way out on a limb here. Not because I feel like this is something I know really well, but just thought i'd mention it IN CASE it just happened to be true....

Is it possible the bore has a rough throat? IE, grooves/marks where the throat was cut with the reamer? or some other roughness?

The reason I say that is, that maybe, when the chamber was cut the reamer left marks perpendicular to the bore (ie, going round the inside of the barrel, versus going down the bore)

I was just thinking, if that occurred, maybe you could get leading with a BIG bullet on the throat section, because finally the bullet is big enough to completely fill the area, as it gets squeezed down, whereas before the bullets weren't squeezed enough to have enough friction to start leading

Just a crazy thought. I'm a little bit surprised that your rifle would chamber a bullet that big, but I don't remember what brass you're using, or how thick the walls are, so maybe its not unusual for that to be able to chamber.

Or, your chamber is on the big / sloppy side, which makes me think about a reamer running with wobble / dull blades.... cutting a slightly oversize chamber, and maybe cutting a rough throat too

Given what you said, I really doubt at least light lapping would do any harm and very well might do some good. But.... since it shoots .431 bullets w/ barely any leading as u mention, it might not be worth the risk/effort.......

Anyways. Just a few random thoughts. Whatever happens, good luck with the rifle! :)

[LUTNIT]

I took jethunter's advice and tried the bullets with 44 special load data (5.5gr Reddot) since it has such a tiny bearing surface. Shot fine (about 4" low at 50yds) and ran a bore snake down the barrel at the range. Took the bolt out, looked down the barrel, and it looked like there may have still been leading (couldn't quite tell since there was still quite a bit of dirt). Brought the rifle home, ran a single solvent soaked patch and dry patch down the barrel, and no more lead! So I guess it really was just far too small of a bearing surface for the velocity I was trying to achieve. I'm not sure why I didn't think of that before.

[TCFAN]

My Marlin 44 mag is the cowboy model with the 20 inch barrel. It is not MC.I tried a lot of different style boolits and the one thing I noticed was that as I went up in diameter the accuracy got better and every time a gas check was tried leading stopped.
I finally settled on a Accurate mold that drop a 230 grain round flat with a gas check at .434 dia. I lube in a .4345 H&I dia and size in a Lee .433 size die.Had a new size plug made for my Lyman M die so that my boolits would not be sized down when they were seated.
I use this boolit with home made gas checks over 10 grains of Unique and I get very good accuracy and zero leading.Very seldom do I have to run a cleaning patch through the barrel.My Chrony say this load is going 1400 fps.It does all i want in this rifle...............Terry