Marlin micro-grooves

[Wrbjr]

I have a 336. Purchased it used. I just purchased dies for reloading 30-30. I understand the micro grooves are a bit touchy with cast? Its not where I can inspect it at the moment... How does one know if the 336 has micro grooves?

[tacklebury]

Typically just need to make sure it's full bore +.001. Sometimes hard if they are overbore to get a good fit. Better off to slug it first to see.

[wgg]

The barrel will be marked Micro Groove, most advise 2 to 3 thousand over, to seal the micro groove barrel. May want to slug your barrel.

[shotman]

Dont try to drive them 4000fps normal loads work fine Look at muzzel end it will look a small maze
I think 12 grooves ???

[tacklebury]

.30 caliber -- 16 grooves, .030" wide and .002" deep (this would be changed in 1958 to 22 grooves .024" wide, and .002" deep; and then again in 1968 to 12 grooves, .040" wide, .0028" deep)

From http://www.leverguns.com/articles/fryxell/microgrove-barrels.htm

[GREENCOUNTYPETE]

I have a 336. Purchased it used. I just purchased dies for reloading 30-30. I understand the micro grooves are a bit touchy with cast? Its not where I can inspect it at the moment... How does one know if the 336 has micro grooves?

lies , they just don't want you to know how well it works for some reason

most 336 do have them , mine does

think about it this way you can put your car on 4 skinny little tires or 12 tires what is going to allow you to make a corner faster bearing surface on the road tells you that 12 tires will give you better traction

the only difference is that a micro groove may require a slightly fatter boolit to get good fit

but if you get the fit right there ain't nothing wrong with them.

[6pt-sika]

I've got about two dozen of the old Marlin Micro Grooves all for the 444 and I normally size at .432" . In the past I had used .430" and .431" and they actually worked decent . But once I went to the .432" die groups seemed to close up a bit .

My biggest concern in the 444 was with bullets 320 grains or larger . In the slow twist Micro barrels for this cartridge I needed to water quench my bullets when cast from straight wheelweights and then push them kinda hard with H322 , RL-7 or the like . And after I learned all this I've had good or better success with bullets from 320-375 grains in the slow twist Micro Groove barrels in the 444 .

[Wrbjr]

Thanks for all the replies. I will probably slug the barrel to find out what exactly I have before ordering a mold. Looking at RanchDog molds. Now to find the section on how to "slug the barrel". I have seen reference to slugging the barrel and the "throat" as if taking two different slugs? Or did I read something wrong?

[6pt-sika]

Thanks for all the replies. I will probably slug the barrel to find out what exactly I have before ordering a mold. Looking at RanchDog molds. Now to find the section on how to "slug the barrel". I have seen reference to slugging the barrel and the "throat" as if taking two different slugs? Or did I read something wrong?

I've tried just about every lever action mold RD has come up with except the ones for the 338 EX , 357 , 41 and 45 .

Anyway all of those he made besides the ones mentioned above I had very satisfying results !

I've cast for and loaded for around 90 Marlin's so far and I've never slugged the first one !

In the 30-30 I size at .312" , in the 32 Special at .323" , in the 35 REM .359" , in the 375 WIN .379" , the 44 MAG and 444 I now size at .432" and the 45-70 I now use a .461" die . Granted everything I cast is either aircooled or water quenched wheelweights !

[Ziptar]

My 45 Colt 1894 has got a Microgroove barrel that slugs at .451, I've been using bullets sized to .452 and it's been shooting just fine. I think if the twist and bullet weight are right a microgroove barrel does just fine with cast bullets only .001 over even.

[Wrbjr]

I've tried just about every lever action mold RD has come up with except the ones for the 338 EX , 357 , 41 and 45 .

Anyway all of those he made besides the ones mentioned above I had very satisfying results !

I've cast for and loaded for around 90 Marlin's so far and I've never slugged the first one !

In the 30-30 I size at .312" , in the 32 Special at .323" , in the 35 REM .359" , in the 375 WIN .379" , the 44 MAG and 444 I now size at .432" and the 45-70 I now use a .461" die . Granted everything I cast is either aircooled or water quenched wheelweights !

That's encouraging as the more I read about slugging a barrel the less I want to hassle with it. I think I may skip it and see how it goes. I can always do it later.

[6pt-sika]

That's encouraging as the more I read about slugging a barrel the less I want to hassle with it. I think I may skip it and see how it goes. I can always do it later.

As long as you stay with aircooled or waterquenched wheelweights you should be fine .
The molds Ranch Dog makes are at those diameters for a reason :wink:

[Wrbjr]

As long as you stay with aircooled or waterquenched wheelweights you should be fine .
The molds Ranch Dog makes are at those diameters for a reason :wink:

I have wheel weight ingots... and range lead and pure lead. All marked so they don't get mixed up. Will order that RanchDog mold and give it a try.

[Marlin Junky]

Just a heads up when selecting powders for your Marlin... the post '55 336 barrels like slower powders; i.e., slower acceleration for a better initial grip at the boolit/rifling interface. Sometimes the powder selection can make a big difference. For example... I achieve the same accuracy with the same boolit design and alloy but at 300 fps faster velocity simply by changing the powder selection from SR4759 to the slower AA2200. Yes the cost is 60%+ more powder and increased muzzle blast and recoil; however, 300 fps is not to be sneezed at when dealing with 345 grain 44 caliber boolits. I've tested this over and over again and have achieved the same results even when the slower powder produces significantly more pressure (approx. 60% more pressure according to QuickLoad). Based on my experience with other guns and listening to others' experiences, I'm sure this will apply to any rifle/carbine with shallow rifling. The original Ballard rifled 336's made up to about 1955 don't care what you burn in them... especially the .35 Remingtons with their 7, .005" deep grooves.

BTW, save the pure lead for later and start shooting boolits in the 15-16 BHN range.

MJ

[TXGunNut]

Interesting observations, Marlin Junky. Is barrel length a consideration?

[Wrbjr]

Just a heads up when selecting powders for your Marlin... the post '55 336 barrels like slower powders; i.e., slower acceleration for a better initial grip at the boolit/rifling interface. Sometimes the powder selection can make a big difference. For example... I achieve the same accuracy with the same boolit design and alloy but at 300 fps faster velocity simply by changing the powder selection from SR4759 to the slower AA2200. Yes the cost is 60%+ more powder and increased muzzle blast and recoil; however, 300 fps is not to be sneezed at when dealing with 345 grain 44 caliber boolits. I've tested this over and over again and have achieved the same results even when the slower powder produces significantly more pressure (approx. 60% more pressure according to QuickLoad). Based on my experience with other guns and listening to others' experiences, I'm sure this will apply to any rifle/carbine with shallow rifling. The original Ballard rifled 336's made up to about 1955 don't care what you burn in them... especially the .35 Remingtons with their 7, .005" deep grooves.

BTW, save the pure lead for later and start shooting boolits in the 15-16 BHN range.

MJ

Okay. I have a hardness tester so will head in that direction. Which brings up my original question or one of them anyway. Based on the serial numbers or model number is there any way to tell the year of this rifle? And does that info lead me to any knowledge of what grooves are in this Marlin specifically? I realize it has micro-grooving of some type but was just curious if anyone else out there with certain year models have already invented this wheel.[smilie=2:

[6pt-sika]

Okay. I have a hardness tester so will head in that direction. Which brings up my original question or one of them anyway. Based on the serial numbers or model number is there any way to tell the year of this rifle? And does that info lead me to any knowledge of what grooves are in this Marlin specifically? I realize it has micro-grooving of some type but was just curious if anyone else out there with certain year models have already invented this wheel.[smilie=2:

My water quenched wheelweights have a hardness of about 12 I think and thats been fine for my applications in the 444 and 45-70 . Before all I ever used was aircooled wheelweights at about 9 to 10 I think and they did fine until I got to the heavier weighs .

In the 444 and 45-70 I could most likely do everything I need with H322 . I also use some RL-7 and Varget for my 400 grainers in the 444 but thats the only real difference I need !

Now with that being said I do and will continue to use IMR8208 , XMP2015 , H335 , H4198 as well as the 3 powders mentioned previousely .

Micro Groove started in the 336 rifles in the mid to late 50's I think 55 or 56 actually . Those all being 30-30 , 32 Special and 35 REM . Obviousely they started Micro in the 444 at it's inception in 1964 . In the 45-70 "supposedly" the first 8000 or so in 1972 had Ballard and then after that until 1998 or so they were Micro Groove . The 444 also supposedly went to Ballard in 1998 .

[6pt-sika]

FWIW , all my hardness numbers came from bullets I cast and then tested with a Saeco hardness tester .

[Marlin Junky]

Okay. I have a hardness tester so will head in that direction. Which brings up my original question or one of them anyway. Based on the serial numbers or model number is there any way to tell the year of this rifle? And does that info lead me to any knowledge of what grooves are in this Marlin specifically? I realize it has micro-grooving of some type but was just curious if anyone else out there with certain year models have already invented this wheel.[smilie=2:

I know it's a pain to count grooves but approximately 1968 (which was an AD date code) Marlin started cutting their MircroGrooves a tiny bit deeper and using less of them, reducing the number of .30 caliber grooves to 12 from as many as 22. It's pretty safe to assume that if you don't have an alpha date code, you've got the last variation of microgrooves. For starters, I would shoot the largest boolit that will chamber. Just for the heck of it, try a Lee 312-185.

MJ

[Char-Gar]

Marlin MG barrels are interesting as they are quite a variety of bore specs. However, then "tend" to be larger in both land and groove size than a nominal .300 X 308. I have two MG 30-30s..a 1960 version runs .305 X 309 and a 1973 goes .302 X 309.

In picking a bullet for the 30 cal Marlin MG barrels, attention needs to paid to nose diamters. SAECO makes a scaled up version of their 30-30 bullet for the .303 Brit. It is a lousy bullet for the .303 British, but the larger nose and body make it a crackerjack 30-30 MG bullet.

It is my understanding that Ranch Dog designed his bullet with the the Marlin MG barrels in mind. That would be a good place to start, but the Saeco is also a good bet.

For the very large 1960 Marlin Texas, I had Mountain Molds make me a bullet with a tapered nose (.304 - .307) and a .310 body. It is great in this rifle, but not worth a hoot in any other.

[Wrbjr]

I now have the 336 in my possession. It is a model 336W if that means anything.... the serial numbers have no letters at all....

[Marlin Junky]

The "W" in the model designation simply means the wood is not walnut. I think they should have used a "B" for birch, but that's just my opinion. Your non-alpha character serial number indicates 12 MicroGrooves in the neighborhood of .0027" deep which is actually just about the same as the new "Ballard" rifling. A boolit with a .302" to .303" nose and .310" body should be fine... I'd try SAECO 305.

MJ

[Wrbjr]

Cool.... thanks for the tips. Will look up the SAECO 305...

[JIMinPHX]

If your barrel has a dozen or more lands & grooves, then it's a microgroove. I've been told that there are 3 different flavors of microgroove in .30 cal, but I've only messed with one, which I think was the 12 land version. I believe that the other two versions have more lands & grooves. The one that I messed with shot cast better than it shot factory ammo, right up to the full velocity of factory hunting ammo in the same bullet weight.

[pls1911]

Life with Lead and Microgroove Barrels is really pretty easy.
Cast fat, size fat (.311), heattreat, lube, load, shoot.
Anything more is personal preference.

My personal preference is RD 165 or SAECO #316, cast at 9 bhn, heat treated to 28 bhn, lubed through.312 die to seat the check, then double lubed with JPW/LLA, loaded over 26 grains of Reloader 7.

Accurate in early guns as well as microgroove guns, punches full length through pigs, or through both shoulders easily.

[Swampman]

Shouldn't be a problem. MicroGroove barrels shoot cast just fine.

[mroliver77]

I have a 30-30, 35 Rem and 45-70 with MG barrel. I have found as long as the boolit fits well they will handle any alloy as long as pressure is correct for that alloy.
Bore riders need the fatter nose as many have stated. I have an LBT 150 LFN(I think) that is a full diameter boolit. It fits perfect in my 30-30 throat and shoots very well. Cast from water dropped wheel weights IU can run max loads of H414 with great accuracy and no leading. In fact this gun has never leaded with any boolit.
J

[Ed in North Texas]

Okay. I have a hardness tester so will head in that direction. Which brings up my original question or one of them anyway. Based on the serial numbers or model number is there any way to tell the year of this rifle? And does that info lead me to any knowledge of what grooves are in this Marlin specifically? I realize it has micro-grooving of some type but was just curious if anyone else out there with certain year models have already invented this wheel.[smilie=2:

Try http://oldguns.net/sn_php/marlinlookup.php for year of manufacture

[Suo Gan]

I always thought the W stood for Wal Mart :). I have a W and it wears walnut stocks and not birch, has the bullseye and everything. I have also seen barrels stamped micro groove and they were ballard. The folks at Marlin got confused from time to time I guess. Anyway, I like RD 311 165 RF in mine.

[Wrbjr]

Try http://oldguns.net/sn_php/marlinlookup.php for year of manufacture

Nice site. I entered my numbers but got no answer. Evidently mine is newer than the format on the website which seems to go to 1990. First two numbers on mine are 91. So I would guess it was made in 91?

[6pt-sika]

Nice site. I entered my numbers but got no answer. Evidently mine is newer than the format on the website which seems to go to 1990. First two numbers on mine are 91. So I would guess it was made in 91?

Yours was made in 2009 .

[Wrbjr]

Yours was made in 2009 .

09? Ok. Thanks. I guess there is some cryptic formula involved. LOL Anyway its good to know.

[kingstrider]

The barrel will be marked Micro Groove, most advise 2 to 3 thousand over, to seal the micro groove barrel. May want to slug your barrel.

Not always the case, I have several MG Marlins that are not marked as such. With a 30-30 the best way to tell is to count the grooves.

[SkookumJeff]

I've got about two dozen of the old Marlin Micro Grooves all for the 444 and I normally size at .432" .

Am I reading this right, you have a couple of dozen Marlins all chambered for the 444 Marlin? I thought I was out of control collecting Marlins LOL, I've only got half that number and in various chamberings. You sir, are the man.

Interesting information about using slower powder for the Microgroove barrels. I appreciate that information, in theory it makes a lot of sense. I will test that theory out next year.

[1kshooter]

:guntootsmiley:6pt-sika is a funny guy...don't talk to him or you will be scrambleing to get your hands on a 444...or even a 444Magnum:kidding:
the man has got skills when it comes down to closing the deal on game with cast bullets and the 444

I have had the same issues with tiny bullets in my 1895SS MG Marlin 45-70 switched to Ranchdog bullets that were the right size and groups shrunk in half and leading is a thing of the past!
Jonathan