Marlin Micro-Groove Rifling
BY Herschel Smith
2 years, 2 months ago
Writer Nick Harvey (from Australia) addresses a question from a reader.
Q: For years Marlin promoted Micro-Groove rifling as enhancing the accuracy of their rifles. If this is true, why don’t they use it on their big-bore rifles in .444 and .45-70? This has got me wondering if Micro-Groove rifling isn’t just another sales gimmick.
– Dave Edwards
A: Over the years I’ve tested quite a few Marlin rifles which had Micro-Groove rifling and found them to be very accurate.
For a while it was used on big-bore rifles, but then a problem reared its ugly head: the fine rifling does not work well with lead bullets unless you are super careful when reloading with regard to the alloys and velocities you are using.
Many handloaders found that when using lead bullets, especially at higher velocities, Micro-Groove barrels leaded up badly.
Marlin got so many complaints about this that they went back to ‘regular’ rifling, which Marlin calls Ballard-type. I believe the .30-30 and .35 Remington still had Micro-Groove rifling, because these calibres are generally used with jacketed bullets.
Ruger has now begun limited production of Marlin lever-guns under its ownership, and so far only of the Model 1895 in .45-70 with standard six-groove barrels. It’s not yet clear whether they’ll use Micro-Groove rifling future production.
On the subject of accuracy: back in the 1960s Marlin claimed a Micro-Groove barrel was 25% more accurate one with than conventional rifling. True or false? Search me! I’ve never noticed any difference when shooting lever-guns with either type of rifling.
Great answer, and thanks for the perspective and information. I didn’t know that.
I was talking to an FFL a few days ago about Marlin’s production line, and he said that word on the street is that the 30-30 won’t be the next rifle they produce. I forgot which one he told me was next, but I hope it’s the .35 Remington. I don’t think it was. Of course, there are still Marlin 336s in .35 Remington to be had, but the ones in excellent condition are going for > $1500.
If any FFLs out there are reading and have access to more information on what Marlin (Ruger) is producing next in line, let us know in the comments.
I’d like to have one. On a final note, I’ve never seen 30-30 ammunition that was unjacketed, so his answer makes good sense.
On August 25, 2022 at 12:31 am, Elmo said:
I have two Marlin lever guns, both 1894s. One is a .41 Magnum, the other is a .44-40 Davidson’s distributor exclusive, of which only 325 were produced. I’d love to see Ruger/Marlin make them both again in blue and walnut, just like mine. They’re beautiful.
I have Ruger Blackhawks in calibers to match both my Marlins.
If they made this rifle in .357 and .44 Magnum I’m sure they’d sell like hotcakes. After all, doesn’t every grownup cowboy want a revolver/levergun combo?
Regarding micro-groove rifling, I don’t think we’ll be seeing Ruger making a return of that idea again.
On August 25, 2022 at 6:51 am, Nosmo said:
Micro-Groove Rifling…..About 40 years ago in either Handloader or Rifle magazine – I can’t remember which one – (different magazines with overlapping readership from the same publisher, Wolfe Pubs) some Anal / OCD shooter did the deep dive on what lead bullets worked best in a microgroove Marlin .45-70.
Turned out none really did, but IIRC the “least worst” was a custom mould he had made in which the bullet-to-rifling contact area was 14MM long, and the harder the cast the better, IIRC he got the best results with alloys in the Brinnell 20-22 range (pure lead is 5, Lyman #2 is 16).
On August 25, 2022 at 12:41 pm, =TW= said:
Walnut/blued 1894 in .357 like Elmo^^^ said. Make it with a barrel band, not a fore end cap.
Until then I can get by with my 1894 Trapper.
On August 25, 2022 at 2:53 pm, Fred said:
Anybody know what happened to GB61?
Hopefully nothing and we’re just boring to him ;-)
On August 26, 2022 at 5:15 am, SamlAdams said:
Haven’t seen any commercial manufacture .30-30 that is not jacketed. But routinely hand load 170 gr hard cast gas checked flat points at around 1700fps as “fun” rounds for the range. But shoot them out of a circa 1911 Savage 1899 and a new Henry. No noticeable leading in either, though the Savage seems to like them a bit more.