Marlin Micro-Groove barrels

Yes .......................................I discovered real quick lead don't like copper with a re-bored 336 from 30-30 to 38-55
 
Thank you for that, I'm currently fighting with a new Marlin 30-30 with micro groove rifling to shoot cast slugs, I've got it to shoot well(under 2" groups) with slugs that are PC coated up the nose but they chamber very tight with coating on the nose ( that micro groove doesn't seem to have much free-bore). These rounds feed and shoot wonderfully in the wife's Winchester.

Too accommodate easier feeding ( the gun is owned and used by a lady and easy feeding is requisite) I carefully coated a bunch of bullets without a spec of coating on the nose, the shank is coated perfectly and sized to .310...the damn things feed perfect but wont group less than 3.5 inches now.

Fryxell is an excellent author & along with Tappin has a complete book out on casting slugs that is an excellent rear on all aspects of casting lead...a bit outdated now that powder coating has revolutionized/simplified the practice, it still has very relevant points. Sorry I dont have a link, it is on my old computer but the entire book is free to download.
 
fingers284 said:
Thank you for that, I'm currently fighting with a new Marlin 30-30 with micro groove rifling to shoot cast slugs, I've got it to shoot well(under 2" groups) with slugs that are PC coated up the nose but they chamber very tight with coating on the nose ( that micro groove doesn't seem to have much free-bore). These rounds feed and shoot wonderfully in the wife's Winchester.

Too accommodate easier feeding ( the gun is owned and used by a lady and easy feeding is requisite) I carefully coated a bunch of bullets without a spec of coating on the nose, the shank is coated perfectly and sized to .310...the damn things feed perfect but wont group less than 3.5 inches now.

Fryxell is an excellent author & along with Tappin has a complete book out on casting slugs that is an excellent rear on all aspects of casting lead...a bit outdated now that powder coating has revolutionized/simplified the practice, it still has very relevant points. Sorry I dont have a link, it is on my old computer but the entire book is free to download.
Click to expand...

That's been my experieince too, powder coating creates feeding problems sometimes.

Powder coating is great for getting a few more fps from cast rifle bullets, and for getting bigger slugs to fit a worn or oversize bore. Milsurps and big bore rifles are perfect for PCing.

But I can lube-size about 4 times faster than I can powder coat plain base bullets so for anything under 1400-1500 fps PCng is not worth the effort for me. Or maybe I'm not doing it right.
 
Last edited:
I have an early Universal M1 Carbine, 4 digit s/n from the 60's, it's all USGI except of course for the receiver, and barrel...which is a Marlin 12 groove "micro groove" barrel. Surprisingly it's the most accurate M1 I ever shot.
 
jethunter said:
That's been my experieince too, powder coating creates feeding problems sometimes.

Powder coating is great for getting a few more fps from cast rifle bullets, and for getting bigger slugs to fit a worn or oversize bore. Milsurps and big bore rifles are perfect for PCing.

But I can lube-size about 4 times faster than I can powder coat plain base bullets so for anything under 1400-1500 fps PCng is not worth the effort for me. Or maybe I'm not doing it right.
Click to expand...

All my pistol bullets I just powder coat now, they feed fine in anything I have and save a lot of time with the amount that I shoot. For rifle I have also found that PC is a headache unless you need to add a few thousandth because of a warn barrel or over sized.

As far as microgroove barreled rifles go , stick to normal lubing , hard lead, size at least 2 thou over what you slug the barrel at and push them hard and you will be rewarded with surprising accuracy. I have a Marlin 444 that will shoot 1.0" for 5 shots and 1.75" for 10 shots at 100 meters. People are blown away with the accuracy and so much for the micro-groove barrels cant shoot and lever action rifles have horrible accuracy.
 
jethunter said:
That's been my experieince too, powder coating creates feeding problems sometimes.

Powder coating is great for getting a few more fps from cast rifle bullets, and for getting bigger slugs to fit a worn or oversize bore. Milsurps and big bore rifles are perfect for PCing.

But I can lube-size about 4 times faster than I can powder coat plain base bullets so for anything under 1400-1500 fps PCng is not worth the effort for me. Or maybe I'm not doing it right.
Click to expand...

This is actually the first "sort of" failure I've had with any PC slugs in a rifle. The first loads I tried in both rifles ( the Marlin & a 94 Win) shot beautiful groups altho hard to chamber in the Marlin . These first loads were at 1450 fps and while they both grouped good, they both shot way low (8 inches at 100) at the highest sight setting (front sights are already low profile). So I sped them up to 1735, they both now shoot high enough and chamber but the Marlin groups fell off considerably.
 
hunter64 said:
All my pistol bullets I just powder coat now, they feed fine in anything I have and save a lot of time with the amount that I shoot. For rifle I have also found that PC is a headache unless you need to add a few thousandth because of a warn barrel or over sized.

As far as microgroove barreled rifles go , stick to normal lubing , hard lead, size at least 2 thou over what you slug the barrel at and push them hard and you will be rewarded with surprising accuracy. I have a Marlin 444 that will shoot 1.0" for 5 shots and 1.75" for 10 shots at 100 meters. People are blown away with the accuracy and so much for the micro-groove barrels cant shoot and lever action rifles have horrible accuracy.
Click to expand...

I must be doing something wrong when i powder coat because i don't save any time. I can lube-size 400+ plain base bullets an hour, can't do half that with powder coating.

The microgroove barrels aren't such a mystery as some people made them out to be. Because the rifling is so shallow, cast bullet fit is extra important. Microgroove barrels need to be squeaky clean for cast, because any traces of jacket material left in the barrel will collect lead even more so than regular rifling. Super hard cast bullets don't seem to work as well as a bit softer alloy. Nothing new there.

fingers284 said:
This is actually the first "sort of" failure I've had with any PC slugs in a rifle. The first loads I tried in both rifles ( the Marlin & a 94 Win) shot beautiful groups altho hard to chamber in the Marlin . These first loads were at 1450 fps and while they both grouped good, they both shot way low (8 inches at 100) at the highest sight setting (front sights are already low profile). So I sped them up to 1735, they both now shoot high enough and chamber but the Marlin groups fell off considerably.
Click to expand...

Haven't tried a lot of PC bullets in lever actions but I don't know why they wouldn't work as well or better than lubed bullets. I have been able to get some extra velocity from PC plain base bullets and and that works well in my milsurps and big bore rifles. A few cents per bullet instead of a few dollars per shot is well worth the effort.

The only real issue I had with PC is that it changes the nose profile and sometimes that means it won't chamber cleanly. So you need to select the right mold compatible with PC and the rifle you're using. That's not a PC problem, just means not all bullet molds are suitable for PC. I found the bore rider .303 bullets didn't work in some 303 rifles after powder coat, but if I started with a 30 cal bore rider it worked nicely in .303 after coating.
 
Last edited:
I loaded up a bunch of hard cast conventional wax lubed& GC (.310) 30-30's yesterday and tried them in both rifles, the wife's Win with open sights & my very poor eyes did under 2.5" (with my eyes I was surprised to get that tight of a group) and with the 3-9 scoped Marlin I was still 4" or more. I suspect I will have to both decrease speed & find a different sight system for that rifle for it to be useful in open sight competitions.
 
I shoot a '69 .444 with 3 different cast bullets and a few loads to great success, I love this gun. I would be interested in trying the same loads in an updated Ballard model to see if I notice a difference. I don't really measure groups but I have some small targets. I really just want to shoot one with a regular stock to see how it feels; mine has the combed stock I think made primarily for scope use, but I shoot with irons.
After buying a ton of cast rounds I'm finally almost through them and want to start shooting PC cast .444, looking for someone with some specific molds for exactly the issue mentioned, i want a shape and profile i think will loan itself to easier loading/cycling after PC. Currently have only PC 30-30 and .303.
 
Both the .44 mag and .444 should have been made with the 1-20 twist instead of the 1-32 [I think] so 300gr bullets could be used.
 
TargetAcquired said:
I shoot a '69 .444 with 3 different cast bullets and a few loads to great success, I love this gun. I would be interested in trying the same loads in an updated Ballard model to see if I notice a difference. I don't really measure groups but I have some small targets. I really just want to shoot one with a regular stock to see how it feels; mine has the combed stock I think made primarily for scope use, but I shoot with irons.
After buying a ton of cast rounds I'm finally almost through them and want to start shooting PC cast .444, looking for someone with some specific molds for exactly the issue mentioned, i want a shape and profile i think will loan itself to easier loading/cycling after PC. Currently have only PC 30-30 and .303.
Click to expand...

After my experience with the micro grooved barrel I would sure recommend a chamber cast long enough to include the free-bore & beginning of the lands before I ordered a mold. You need to know the I.D. dia. of your lands where they are going to meet the bullet ogive. If you plan on just "shake& bake" method to PC your bullets it will add from .0015 to .003 to the bullet nose dia....might be real tight to chamber.
 
I'm not looking to cast or create a mold, didn't mean to insinuate either. But looking at some cast manuals there are molds I've never seen available that I'd like to try and find in someone else's shop so they take my money and run a batch for me unlubed and I'll do the PC and dev.
There are certainly some casts that are tight to chamber even without PC, why I'm curious if some different profiles would better loan themselves to this stuff.
 
You must log in or register to reply here.
Back
Top Bottom