Marlin 336 Microgroove

[SlamFire1]

Hey guys:

Recently came into possession of a like new Marlin 336 in 30-30. It has a 20 inch microgroove barrel. The rifle was built around 1991. Excellent condition, nice crisp trigger.

I have cast a bunch of Lyman 311299 bullets, at 205 grains, and Lyman 311284 bullets at 215 grains. I also have at least ten pounds of AA5744. I have been having fun, practicing offhand with a Ruger #1 in 30-06 with these bullets and this powder. I can consistently hit my 12” gong target offhand at 100 yards, most shots falling within a salad plate sized group. There are always a few that hit the berm too. Not the fault of the bullets or the rifle. Must the wind………..

I have had poor luck with the microgroove barrel in 44 Magnum, and sent that rifle off to Marlin, paid about $200, to have that barrel replaced with a “Ballard” barrel.

So I am wondering, can I get somewhat acceptable accuracy in a microgroove barrel with the above bullets and AA5744. Any suggested loads?

[georgewxxx]

Your biggest problem is the length of your Lyman boolits. The reason I know is Because I just finished loading up 50rds of 6 different weights to try in my 336. To get those heavy long boolits to feed through your action you'll have the base of both of them below the shoulder in your case. I tried bumping the nose flat by sizing upside down. That only works if your alloy is soft enough. If you don't mind shooting single shot only, you can seat them as far out as you like, but remember, you'll never be able to pull a loaded round out of your chamber because of the extra long nose if you don't want to seat below the neck . I'm working with 311407, 311299, 311290, 311291HP, and a Belding & Mull 311165 that's a heavier version(174gr) of Lyman's 311440. I had to squeeze the nose down in a 7mm sizing die just to get 311407 & the B&M boolits to chamber properly. Also make sure your cast bullets are at least .311 before you start sizing or your wasting your time in a Micro-groove tirdy-tirdy. My old records show 23gr of 5744 as max in my Model 54 Winchester tirdy-tirdy bolt gun. That means you'll get about 6500 rds out of your 10lbs. ...Geo

[SlamFire1]

George: Thanks. I only plan to shoot the cast bullets single shot, during offhand practice. But based on what you wrote, if I have future plans to use cast bullets in the tube, I had better go with a shorter bullet.

I am worried whether these bullets will strip out in a microgroove, something that was a problem for me in my 44 Mag M1894.


Never owned a thurty-thurty before. This is a heavy rifle and I figure the recoil will be minimal. I actually dislike shooting the M1894 with full power loads. The thing really kicks.

I will have to check the diameter of my 314299's. I cast a bunch, only shot a few in a No 4 Mk II, but they worked just fine in that rifle.

[35remington]

"I am worried whether these bullets will strip out in a microgroove"

SlamFire, I have heard this concern many, many times in regard to Microgroove rifling. Apparently these theorists figure that shallow rifling doesn't get enough grip on the bullet, so it strips.

Most likely not so. I have recovered many, many rounds of spent bullets from Microgroove 336's and noted no stripping, even with bullets that were undersized, driven either slow or fast. Yours most likely weren't stripping either; they just weren't shooting. If you can show me a stripped bullet fired through a Microgroove barrel using a load that shoots in a "Ballard" barrel that would be a first in my experience. In extreme cases accuracy can go from minute of bushel basket to keyholing, usually a sign that the bullet is undersized.

A few bits of information:

Chambering and throat of the 336 has far more to do with how well it shoots lead than rifling style.

Marlins often like oversize bullets but this often has more to do with how they're chambered than any dimensional problems with the barrel. Marlins tend to favor all body bullets over bore riders. Some of your moulds are, I believe, bore riders. In your .44 caliber a .430" bullet won't get it done - you've got to go larger than that.

Constrictions in the barrel on 336's happen irregardless of rifling style.

Don't get hung up on rifling style, as there are too many guys here that shoot Microgroove successfully with lead. Look at your chamber first, and note its limitations. Then you'd be placing the blame where it belongs.

I'd suggest the Lee Soup Can at .311" diameter for starters if you want to hit the "easy" button. Some of your bore riders likely have a nose that won't ride the bore in your Microgroove rifling. A bullet choice problem, not a rifling problem.

[georgewxxx]

Today's results show my 336 favoring the bore riders . Seated to past the shoulder, all three riders out-shot the full body ones using the same powder charge 2 to 1. the 311284, 311299, and 311299 all shot inside 2.5" at 100yds. The load was 30gr of 4350. Remember I said they all where extremely deep seated to almost .25 below the neck. I really expected the 311291HP to out-shoot them, as it's seated to just above the neck, but 2.5" is all I come up with there too. Based on that, I say why not try your boolits and see how they shoot. I alway figure on trying what you have on hand and not worry about what some say won't work. Just watch your seating depth when loading. I'm in a situation where I can just go outside and fire the round if I accidentally seat one too long and it's too long to eject. Most guys can't. It might not be a bad idea to make up a couple of dummy rounds to keep on hand, or keep good records of your seating depth for future use. That load of 23gr 5744 will only fill your cast 3/4 full, so you won't need to worry about compressing anything with either of your boolits....Geo.

[35remington]

"Tend to" isn't a hard rule, for sure, and my post above shouldn't be interpreted as such.

The RCBS 205 FN shoots in my Microgroove rifles, and a lot of the bullet length is engraved by the rifling. It qualifies as bore ride. If something isn't shooting, try something else.

Your bore ride may fit and it may not. In Microgrooves, many do not. All body bullets are harder to obtain in many mould brands, but should be given a fair trial if your bore riders aren't shooting to your satisfaction.

Oldfeller's Group Buy 7mm Soup can, which is all body, shoots when the Lee 7mm 130 bore rider will not in my Model 94 7-30 Waters. Thing is, the Lee's bullet nose is engraved by the rifling when it's pushed in the muzzle end, which theoretically is the "test" to see if a bore ride bullet will work. It doesn't, for whatever reason.

BTW, the rifle qualifies as having "Ballard" type rifling, which is a supposedly better match for a bore rider. Go figure.

Keep trying, and don't get discouraged if first results don't pan out. Cast bullet shooters are a persistent lot, and success along with more knowledge is obtained by not giving up.

[eka]

Slamfire1,
Sorry to hear of your troubles with your 1894 .44 Mag. That has been my shining star so far with cast rifle. My rifle is a micro-groove produced in the late '70's. With a Lyman receiver sight it will put three shots in a clover leaf group at fifty off the bench. The bullet is the RCBS 240 SWC out of straight WW and FWFL lube. My experiences with my 1894 have got me in the market for a Marlin 336 in the near future. With the micro-groove barrel I try to keep the bullets sized as big as the throat will allow, fairly hard, and gas checked.
Good luck,

Keith

[VTDW]

35remington's posts are chock full of absolutely great information about microgroove barrels!! If you want to shoot a microgroove (all my Marlins are microgroove) and cast boolits it would behoove you to read his posts until you understand what he is saying. Ain't nuttin wrong with them.

www.ranchdogmolds.com is a great place to buy molds designed exclusively for shooting cast boolits in your Marlin.

Dave

[georgewxxx]

35, I really like your last statement.

In some of those articles Beagle had us put together that are posted in Castpics & Castingfellows just for questions like Slamfire's. Those plus all the threads here on this board have created exactly what Beagle envisioned for not only newbies, but guys like me that needed a little help on a different in loading and casting project than they've done in the past. I guess I kinda cheated too by trying a condom Speer to set the ground rules so to speak. Even those proved dismal with a 5" group, so I really didn't expect too much from this 336. That's with one of Lyman's old accuracy loads from HB#45 too.

The loads I shot yesterday were pushing hard on the cork of the little tirdy-tirdy cases. Not overloaded by any means, but for me anyway top end. Being a lazy sort, I didn't bother to set up my chronograph, but I could tell that all seemed to have a little more snort in recoil than usual. If all you want is for the boolit to exit the bore your results may not be like mine. Slamfire said all he was looking for is practice ammo, mine are geared up for poking holes in deer. Not that there is a whole lot of difference in velocity from the two, as the tirdy-tirdy is on the low end as far as hunting velocities go anyway. When I first started casting in the early 60's, everything was practice loads. Slowly but surely, I migrated toward hunting loads. Now I rarely try concoct anything but hunting loads for any my guns. ...Geo

[SlamFire1]

SlamFire, I have heard this concern many, many times in regard to Microgroove rifling. Apparently these theorists figure that shallow rifling doesn't get enough grip on the bullet, so it strips.

Most likely not so. I have recovered many, many rounds of spent bullets from Microgroove 336's and noted no stripping, even with bullets that were undersized, driven either slow or fast. Yours most likely weren't stripping either; they just weren't shooting. If you can show me a stripped bullet fired through a Microgroove barrel using a load that shoots in a "Ballard" barrel that would be a first in my experience. In extreme cases accuracy can go from minute of bushel basket to keyholing, usually a sign that the bullet is undersized.


I guess I struck a raw nerve. Well my experience is my experience.

I buy 429" commerical cast bullets for the 44 Mag. I am only casting for the 30 caliber because I could not find cheap 30 caliber bullets. But I was able to get good commerical cast 44 bullets for less than a nickel a bullet.

Well I did have problems with two microgroove barrels on my M1894. The microgroove barrels on these rifles were in a word: horrible. I sent the rifle back twice to replace, in my opinion, defective barrels. The first barrel clearly had some machining ring in the tube and both barrels varied in tube diameter. You could push a patch down the barrel and feel it stop and start as the barrel interior alternately grew larger and smaller. How the barrel interior dimensions could vary so much when gundrilled is a mystery to me. Incidentally, back in the 80’s, discussing barrel quality with the factory guys , they verbally expressed contempt about the barrels at that time. I stopped sending the action back for barrels at the third microgroove barrel. While Marlin replaced two barrels for free, none of them were really better than any other and it was a futile experience and a waste of my travel time and shipping money.

While I owned this rifle for 18 years, I did not shot it much, basically because with those microgroove barrels, it would not accurately shoot lead bulleted pistol ammo. I do not cast my own, I purchase thousands of commercial cast bullets at gun shows, load them, and go shoot. The standard 240LSWC .429” lead pistol bullets would strip out at velocities greater than 1000 fps in a microgroove barrel. It was dismaying to compare 25 yard targets between the rifle and my pistols. Generally the pistol group at 25 yards was equal to or better than the rifle group with the same ammo. This was awful.

Jacketed bullets however shot reasonable well, about 4 inch or less groups at 100 yards.

In 1999 I found out that Marlin was making new “Ballard” barrels. I called up the factory and discussed replacing the microgroove barrel with a Ballard barrel. The gentleman at the factory told me that it would cost $130.00 to get this rifle rebarreled. When I mentioned that I was firing .429 cast bullets, the gunsmith informed me that the rifle barrels were made to SAAMI specs which called out for rifles a barrel interior dimension of .431”. Marlin claimed that their specifications for the barrels were 0.431 + - .001”. Also the factory guys were very positive about the quality of these late 90’s era barrels. I asked the gunsmith to find me a good barrel made to the minimum dimension. The gun smith air gaged a number of barrels and claimed that none were on the low end, I got the basic understanding that the barrels were all .431 with very little dimensional variation. Well that shows that production processes had improved in 18 years.

Marlin had not changed the 1:38” twist of the microgroove barrels nor was the groove depth significantly deeper than the microgroove barrel. In my opinion the difference between a Ballard barrel and a microgroove is a bunch of lands. This is a mistake in my opinion as my Ruger pistol barrels had much quicker barrel twists and were much deeper grooved, and shoot cast bullets very well.

My Ballard barrel shoots cast bullets better and at a higher velocities than the microgroove barrel. When I push a patch through my Ballard barrel, it is smooth. Not a single tight or loose spot in the barrel. Maybe that is why it is doing better than the microgroove.

I have found that fore end tension on these lever guns really effects accuracy. I did some forend glass bedding, soft soldered the forend hanger on the barrel, and my fore end no longer rattles. Then I found that if the forend creeps forward, elevation radically changes at 100 yards.

I do not expect a lever gun to be as accuracy as a bolt, but mine is now accurate enough to keep all shots on a 12" gong at 100 yards. And I am using a Williams Foolproof rear sight, and I changed the front to a big broad square post. I forget from whom I got that from, but I much prefer a post to a gold dot. That's because of all that service rifle shooting I have done.

I appreciate the help, going to size some 30-30 cases and use some of my lyman bullets.

[35remington]

SF, my nerves ain't raw, so don't worry about it. Somebody else would have piped up about their accurate lead bullet shooting Microgroove if it wasn't me. I just happened to say something first. But there are too many other knowledgeable shooters here that also do very well with lead bullets in their rifles who would not have their guns rebarrelled to "Ballard" because they might get something that wouldn't shoot as well.

Most times shooters blame the constrictions in the barrel on the manufacturer stampings and dovetail slots in the barrel, which are supposed to narrow the interior a bit. Ballard barrels can suffer from this as well, so if Marlin has cleaned up its act with Ballard most likely the Microgroove are constriction free as well. Only way to know is to check.

I can relate to what you are saying about barrels. I've had some standard rifled ones that just wouldn't shoot lead bullets. Since standard rifling does not have the "bad rep" some give to Microgroove when speaking of cast, to what do I attribute my poor results?

The answer to that is the same one that answers why your Microgroove wouldn't shoot. Varying interior dimensions in your case, plus a possibly unsuitable chamber and throat. In my case, a badly cut chamber and nonexistent throat. Either way, they weren't shooting, but the rifling type itself had absolutely nothing to do with it.

Can't say whether it would have helped in your case, but given an otherwise decent barrel, slight oversized dimensions can be cured by selecting the right diameter bullet.

It's pretty well known here that these larger dimensions are necessary to get some Ballard or Microgroove Marlins shooting, irregardless of actual barrel dimension in many cases. The throat types common to leverguns often make the larger diameters necessary, at least in my experience.

FWIW, Pope's superaccurate lead shooting barrels were very similar to Microgroove in that many of those he turned out had many small lands and grooves rather than a few larger ones like a standard barrel.

It's not the rifling style that's inaccurate; it's the execution by the manufacturer that determines whether a barrel shoots or not. Sounds like you had an uphill pull with yours; I've been more fortunate and that's why I have no regrets nor second thoughts when purchasing a Microgroove Marlin. Any problems with barrel constrictions, dimensions or twist likely would also have existed had Ballard rifling been the standard in past years. Remidies can be applied to problem barrels and owner upgrades that do not involve rebarrelling have been discussed on this forum.

1-38 twist is thought to be a bit slow these days. I understand that Marlin has corrected that, but I don't have a new .44 to check. Many get 1-38 to shoot just fine.

[35remington]

George, can't argue with your results. More power to ya.

My .45-70 Microgroove does well with all body bullets because bore riders usually don't result in an OAL that works through the 336 action, but I have a Redding/Saeco GC bore ride design that weighs about 480 grains which shoots super accurately. Doesn't have anywhere to crimp when seated to 2.57" but doesn't seem to be affected by setback in the magazine even so. I think it's starting to take up too much case room but it penetrates a whole 4 foot stack of wet newspapers and keeps right on going. At any speed of 1100 fps or more.

My older .35 Remington Microgroove rifle doesn't care what lead bullet design it gets. It shoots them all.

[georgewxxx]

A friend related to me how he had his 44mag Ruger semi-auto worked on to get the leade tapered at a shallower angle and it made a shooter out of a club. Being a cast only shooter, he was willing to pay whatever to get the darn thing to shoot lead. I'm wondering if you lucky guys that brag about how well your microgroove guns shoot have a different leade than us poor souls with the so-so guns.

http://www.leverguns.com/articles/paco/chapter23.htm

Being lever gun shooters, we should all read Paco Kelley on how to make levers work better. I know it helped mine ...some... Geo