Marlin 336 30/30

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grizz59

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Hi, new to the site. I have a early 60's Model 336 RC 30/3 Micro Groove. The bullets tumble out of the gun and the gunsmith I took it to told me the barrel is toast. The gun is in mint shape and holds sentimental value as it was given to me from my dad. I am wondering what the odds are to find a barrel for it or another donor gun and swap barrels out. Are there any other options for me. Thanks Colin
 
Make sure the barrel is good and clean and look at it using a light in the chamber. If it still has decent rifling and looks ok I would try shooting some ammo made with cast bullets.
If the barrel is oversize the cast bullets should shoot better as the lead will expand to seal the bullet
you might be able to save yourself from re barreling it
 
The only place a barrel wears is at the throat. Somehow I doubt that a 30/30 could significantly wear the throat. It'd take tens upon thousands of rounds to do that. My bet, as someone noted already is that the barrel is just really dirty.

Even if the throat is badly worn, you can get around that problem by hand loading and seating the bullets long.


Deathrawt said:
Make sure the barrel is good and clean and look at it using a light in the chamber. If it still has decent rifling and looks ok I would try shooting some ammo made with cast bullets.
If the barrel is oversize the cast bullets should shoot better as the lead will expand to seal the bullet
you might be able to save yourself from re barreling it
Click to expand...

How do you imagine a barrel becomes "oversize?"
 
Oversize cast bullets could work and would be less expensive than rebarreling. Some of the micro groove barrels don't like cast bullets or need a lot of trial and error to find a bullet diameter they like.

Ron Smith in Wimbourne AB is a barrel maker I've dealt with. He can rebore your old barrel to 38-55 for about $450 installed, or put a new 30-30 barrels on for about $800-$900. PM if you want his ph#.
 
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Is the crown on the rifle good? I would be skeptical of a gunsmiths opinion on the barrel being toast, unless he has experience with microgroove barrels. They typically have very shallow rifling and might look worn out to someone used to more standard rifling.

Since it has sentimental value, you could always find another 336 RC and get a gunsmith to swap barrels. If Ron Smith is still doing work then that would also be a great way to go.

Chris.
 
As others have mentioned it seems unlikely it is truly worn out. Dirty barrel, damaged crown or an oversized bore are more likely than it being worn out. Slugging the bore to determine its size will help rule out a .32 Special barrel mislabeled as .30-30, as this has happened before. Exhaust these possible causes before proceeding with altering the gun unnecessarily.
 
grizz59 said:
Hi, new to the site. I have a early 60's Model 336 RC 30/3 Micro Groove. The bullets tumble out of the gun and the gunsmith I took it to told me the barrel is toast. The gun is in mint shape and holds sentimental value as it was given to me from my dad. I am wondering what the odds are to find a barrel for it or another donor gun and swap barrels out. Are there any other options for me. Thanks Colin
Click to expand...

Find another gunsmith who does not use the term "toast" to describe a problem.
The gun likely needs a good scrubbing with a bronze brush and lots of solvent like "Sweets" or "Hoppes9" with lots and lots of elbow grease along with lots of clean patches.
 
Micro-groove barrels can be finicky. Add that to the fact that here are more than one style of
micro-groove configurations, and it can yield issues.

First thing I would do is clean up that barrel thoroughly.

Then try a bullet/cartridge from another maker. I had one of these 336's that tumbled a certain
manufacturers ammo badly, but shot another brand perfectly well. Reloading for it gave similar
results. Winchester bullets tumbled/keyholed, but Speer and Hornady bullets shot just fine.

I highly doubt that your 336 barrel is "toast" I ran several hundred jacketed bullets through the
336 I mentioned above, and it showed no visible signs of throat erosion [borescope used]
Regards, Dave.
 
Barrel is stamped marlin336 rc 30/30 micro groove. Will give it a good cleaning and try different ammo to see if this helps. Toast is my term not the gunsmith. Shooting at paper at 50 yds. yields 6 hits out of 15 and holes that look like I stuck my thumb through the paper.
 
jethunter said:
Oversize cast bullets could work and would be less expensive than rebarreling. Some of the micro groove barrels don't like cast bullets or need a lot of trial and error to find a bullet diameter they like.

Ron Smith in Wimbourne AB is a barrel maker I've dealt with. He can rebore your old barrel to 38-55 for about $450 installed, or put a new 30-30 barrels on for about $800-$900. PM if you want his ph#.
Click to expand...

Or better yet, have Ron re-bore the tube to .35-30 with a gain twist that ends up as 1 in 12". ;)
 
grizz59 said:
Barrel is stamped marlin336 rc 30/30 micro groove. Will give it a good cleaning and try different ammo to see if this helps. Toast is my term not the gunsmith. Shooting at paper at 50 yds. yields 6 hits out of 15 and holes that look like I stuck my thumb through the paper.
Click to expand...

Mismarked barrels that don’t correctly represent the chambering/bore diameter aren’t overly common, but far from rare enough to blindly trust the markings as correct.

Use the advice given here to work through and figure out why it isn’t stabilizing the bullets before you throw more money at fixing the problem.
 
In my mind the one thing that will keyhole a bullet is pressure. What bullets? How old are they? Center of gravity vs center of pressure ratio will yaw a bullet. How good is the crown? Is the bullet getting a pressure kick from one side as it exits the muzzle? I can't imagine the barrel is worn out on a 60's 30-30, clean it really good and measure it if you can. It's unlikely but possible you have a misstamped 32, that would def cause a muzzle exit issue. My steps would be clean it good and try it, then change bullets and try it. Have it measured if you can,if it actually 30-30 I would try a recrown before a rebarrel. JMHO
 
My experience is hunting rifles from decades ago were not cleaned all that often. As already mentioned, spend a good amount of time scrubbing that barrel first. Don't get discouraged. You will likely be at it for a while!!
I acquired a Win 32 special from an old friend. Still cleaning that barrel. He said it tumbled. Some of the ammo he gave me that he was using was 30-30. No wonder it was tumbling.
Another 'quick' check to determine calibre is to simply place the bullet in the end of the barrel (lightly) and see how well it seats. It should not fall into the barrel! If it's a 32 special, the 30-30 will seat up to the brass. After that, try slugging it (again, as already mentioned) and measure the slug afterwards.

Before any of that though, clean it really, really well.

cheers,
 
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