I'd suggest a cood cleaning to be sure of no copper and lead fouliing as a first step in diagnosis, but someone with more knowledge may know better.

 

Thanks 48vintage, been there done that. Took the gun to 2 gunsmiths and both did there magic and confirmed the barrel is clean.

I personally cleaned the barrel with copper solvent and mercury to make sure of no copper and lead.

If we slug the barrel only in the throat area there is almost no groove there. At the crown the grooves are nice and clear on the slugs.

Peet

 

What kind of copper solvent were you working with?

It took me a while to learn that they are not all created equally. It took me longer to admit it to a couple of guys I shoot with. I had been using Barnes CR-10 and Sweet's 7.62 with what I thought were good results. A buddy told me to give the Bore-Tech Eliminator a try. I thought he was just being a blow-hard, but darned if he wasn't spot on. I really hated admitting to him that he was right. When I used that Bore-Tech Eliminator in bores that were previously 'spotless' surprised the dickens out of me. The first patch through a 'spotless' bore came out the prettiest shade of blue... Two hours later, I was confident that all traces of copper fouling had been removed. Anyhow... It sure as heck can't hurt.

 

It is not common to Marlin barrels.

 

Here is a group out of my .35 336 it too tumbled bullets til I cleaned it very good.

 

Just the fact that one gunsmith said it was common in Marlins calls his competence in to question. I have yet to see one in the scores I have owned or worked on that showed anything approaching so much throat wear -- but maybe 20 of them that LOOKED that way before getting the copper fouling out.

 

According to Wikipedia - "Designed for factory loaded ammunition, Microgroove barrels have a reputation for accuracy problems with centerfire ammunition handloaded with cast lead bullets due to the increased bore diameter generated by the shallow grooves. Use of oversized cast bullets has great effect on solving this problem, restoring accuracy with cast bullet handloads to levels seen from Ballard rifled barrels.[SUP][4][/SUP] Early Marlin .30-30 microgroove barrels had a twist rate of 1 turn in 10 inches optimized for factory ammunition with jacketed bullets; later Marlin .30-30 microgroove barrels show a twist rate of 1 turn in 10.5 inches which improves accuracy with cartridges loaded to lower velocity than standard."

Further, I have a vague recollection of having read somewhere that the microgroove had also developed a reputation for short life in rifles of "higher velocities". I think I may have read this somewhere in Wikipedia but not sure.

However, just because it is in Wikipedia don't make it gospel but it is something to consider. Personnally, I have never had problems with microgroove.

 

As you said just because it is in Wikipedia doesn't make it gospel...and that is certainly true in the inaccuracy of their statement!

First - bore (not groove) diameters in 30-30 micro grooved barrels ran around .305" up until the mid 1960's after which it was changed to .300/.301. The three micro grooved Marlin 30-30's I have worked with (1956, 1960, 1977) all had .308" groove diameters which is standard for any .30 caliber barrel.

Second - All three rifles DID NOT REQUIRE OVERSIZED CAST BULLETS to shoot well.

Third - All had a 10" twist as do current 30-30 Marlins. There never was a 10.5" twist barrel!!!

w30wcf

 

You have break free an a good brush it an let it soak for a while then scrub some more then use auto transmission fluid for oil an try that

 

I'm not sure what you mean by "almost no groove". If that is correct then you have fowling in the grooves. If you mean there is almost no lands, then there is erosion.
What were the dmensions of the lead slugs from the throat area?

 

I have a marlin made in 76. It has micro groove. I do know this as far as accuracy is that micro groove likes jacketed bullets if you are going to shoot cast bullets you need ballard rifling. Mine is a old wore out marlin but the rifling is pretty in my barrel. But I always have cleaned mine well. Ive heard of this in other rifles when using corrosive primed ammo.

 

if you are going to shoot cast bullets you need ballard rifling.

I have to disagree with this statement, Micro's shoot casts just fine.

 

PVDW,
I have a 336A made in 1977 that has close to 3,000 rounds through it and it is as accurate as ever with strong rifling from the throat forward.
Even if your rifle does have some throat erosion, that should not make much difference in accuracy. I have a 788 Remington in 30-30 with about 15,000 rounds through it and the throat has moved forward close to .200" and it still shoots very well.

Does your rifle have a scope? If so, I wonder if there might be a scope problem?


By the way the aforementioned 336A has micro groove rifling and SHOOTS CAST BULLETS AS WELL IF NOT A BIT BETTER THAN ANY OF MY OTHER BALLARD RIFLED LEVERGUNS!!


w30wcf

 

I have found that my 30-30's do get pretty crappy the first two inches from the chamber. If you run a patch back & forth you can feel it drag right there. I run a wet patch into it and leave it there on the rod to soak a while, then repeat if needed. A bronze brush does wonders too.

Figure I'm close to 2000 rounds down my first 336C and it still shoots fine. The operator's another story :flute:

 

Thank you for all the replys. I was a bit skeptic about the comment on the Marlin barrels and that is why posted here.

I am fairly sure the barrel is clean and want to try and exclude that as the problem but I will take it to another gunsmith just as a final try.

What bugs me is that mono metal bullets works perfectly in this gun. 1" at 100m is no problem. :hmmmm::hmmmm:

Peet

 

Throat erosion from too hot of ammo?

Have you tried more than one recipe for your reloads? Different bullet weights? Powder?

Myself, I would be inclined to follow up with more cleaning.

I think I would tend to somwewhat disagree with what Wikipedia has to say about firearms. Seems that there is some regurgitated information listed that has been disprooven by MO member's more knowledgable than I.

 

I can not see 30-30's getting too "hot". A magnum maybe, but 30-30 cases will blow themselves apart if you go too far over max.

 

Hal,
The case is a gasket and thus is only as strong as the metal surrounding it. In my 788 30-30's I have run loads that are approaching 55,000CUP and the cases are fine even after 15+ reloadings.

That being said, I would never shoot any 30-30 cartridges loaded above 38,000 CUP in a levergun.


w30wcf

 

With all due respect I would suggest that you get some JB Non-Imbedding Bore Cleaning compound and, using a good .30 cal jag (not a loop tip), and tight fitting cotton patches clean the heck out of it paying particular attention to the leade-throat area. Follow that up with Break-Free CLP. I'll bet that you will be amazed at how much crap comes out of it and that the missing rifling in the throat area reappears. I have used JB compound on fouled bores for 40 years or more and it is amazing stuff.

 

Have a older Glenfield and it shoots storebought lead and home cast Lee bullets weights from 130 gr. to 170 gr. better than I can aim them. The only problem is fouling and everyone here has said, you have to brush it out, after use. Learned quick to be careful putting together cast loads it can be a bear to clean up a badly leaded barrel.

 

What kind of copper solvent were you working with?

I use Robla Solomil as a copper solvent.

Peet

 

Not sure what Robla Solomil is, or how well it works - - might have to do some internet searching to learn more about that solvent. Can you even get Bore-Tech Eliminator in South Africa?

 

.

I agree with Lunarphase. Cast bullets work great in my Marlins. I think the OP is being given a lot of BS.

 

The micro groove might just shoot cast bullets fine. Ive just stuck to recomondations made about jacketed bullets and micro grooving. Its not BS. I would imagine hard lead would do better than soft, but Im no expert never reloaded. planning on doing some and Ill learn from here as well.

 

The micro groove might just shoot cast bullets fine. Ive just stuck to recomondations made about jacketed bullets and micro grooving. Its not BS. I would imagine hard lead would do better than soft, but Im no expert never reloaded. planning on doing some and Ill learn from here as well.

Yes.....It's B.S.

 

YUP! What Gator said!! and YES, you will learn a bunch when you start handloading! Even more when you start casting your own - then you will be set free!

Jeff
NRA Life

 

This is why I'll only buy new Marlins. The old ones are junk.

(see what I did there?)

 

:flute: :biggrin:

 

OK yall ganging up on me. I see The truth. Yall win.:ahhhhh:

 

origin of cast bullets don't work well in microgrooved barrels

I think the beginning of this fairy tale started back in the late 1950's. Micro groove rifling debuted in 1955 during the time when many cast bullet shooters were using lead/tin alloys which are too soft for velocities much over 1500 f.p.s. with bullets having a sectional densities greater than .25.

The problem was that some folks wanted close to 30-30 factory velocities with cast bullets and that is not going to be a good result with lead/tin bullets.

In addition, molds back then could vary quite a bit dimensionally and many had undersized noses. Molds today are much better dimensionally than in the 1950's.

Eventually, it was learned (some knew it already) that alloys with antimony were needed for higher velocity bullets but the old fairy tale still persists today.

I personally have worked with 3 different 30-30 rifles that had microgrooved rifling and they all shot very well at 2,000 f.p.s. when the correct alloy was used.

Note that all .22 Marlin rimfire rifles use microgroove rifling and they do just fine with .22 lead bulleted ammo.....

w30wcf

 

You could just ship it back to Remington for a factory barrel replacement, I think that it's about 150.00 for parts and labor.

 

DWB Robla is products made by BALLISTOL CLEVER. Ballistol | Startseite

The Bore tech products I have never seen in SA. It might be around but I never came across it.

I will look and see if I can find it.

Peet