30-30 hits sideways

[Irascible]

A friend was over Saturday with a 1970s era 336 carbine in 30-30. He was complaining that his bullets were hitting the target sideways. Even factory rounds! I pulled the bolt and had a look at the microgroove barrel and could see no problem, it was even clean. It seemed to have some slight rust in the bore just below the muzzle, which went away with cleaning. I don't think that would cause the problem. Someone else claimed nicks in the crown would cause the problem. I couldn't see any but I don't think that would cause this severe a problem either. Any ideas out there?

[Chuck 100 yd]

Are you sure it`s a .30-30 and not a .32 Special??
Factory or hand loads??

[Old Savage]

Slug the barrel.

[earlmck]

I'm with you -- a bad crown would get bad grouping, not sideways stuff.

If this is a rifle he's had a while maybe a trip to the range with different ammo and different shooter is in order. If a new acquisition, have you checked to make sure it's a 30/30 and not a 32 Spcl barrel, even if marked 30/30? (I know that Marlin could produce a "bad-build" on occasion).

After that I'm plumb outta ideas.

[earlmck]

Oh yeah, 'nother thought: 35 Remington is more likely than 32 Special in that age of rifle. If it's a 32 Special the 30/30 cartridge pushed in the muzzle would swallow the bullet easily but not the case neck. A 35 Remington would swallow the 30/30 case clear to the shoulder.

[Blaine]

An Alpha Hotel that I worked with had a 336 that keyholed like that. It had been shot mucho, and it looked to me like copper fouling. The moron liked the "big hole" it put in stuff...made it "hit harder"

[Griff]

Slug the barrel.

+1. It'd be the place to start... IF... it reads ".30-30" on the barrel!

[Hobie]

We had a young man who bought a .35 Rem 336 and a box of ammo. Took it home, shot it. Needed more ammo. Complained that every case was splitting unlike the first box. Was shooting .30-30 in the .35. Funny, he didn't complain about lack of accuracy. I think I still have the cases he brought in as proof we'd sold him bad ammo.

[jnyork]

Not a good idea to have .303 Brit and .30-30 ammo on the bench at the same time.



I'm thinkin' the OP's guy had the wrong ammo. Maybe it says .30-30 on the barrel, could have been rebored and not marked for the new cartridge.

[Blaine]

I have a 336 that was a .35, but reamed out to .358...it is clearly stamped on the barrel.

[olyinaz]

Oh yeah, 'nother thought: 35 Remington is more likely than 32 Special in that age of rifle. If it's a 32 Special the 30/30 cartridge pushed in the muzzle would swallow the bullet easily but not the case neck. A 35 Remington would swallow the 30/30 case clear to the shoulder.

Seems like the best place to start.

Oly

[Irascible]

I never thought that in might be another caliber as it's marked 30-30. I doubt it's been rebored as it has the microgroove rifling. I cleaned it for him and could see no copper fouling problem. I'll call him later and tell him to try a 30-30 in the muzzle
Thanks for your answers

[Tycer]

Keep us posted!

[rangerider7]

The only time I ever had that happen was because of a wore out barrel. RR7

[1894c]

two years ago i bought an old vintage Marlin 336 (24" bbl, 1957)...the gun was old, but in pretty good shape...bore looked shiny...a friend of mine and myself took it out with four factory boxes of 30/30 (170gr. bullet...the Marlin came with a Willams receiver sight too) and the best we could do was a 30" group at 50 yards...in the end we discovered that the barrel was whipped... :)

[Irascible]

We only got as far as stickingk a 30 caliber bullet into the muzzle. Only goes about 1/2 way. So, it is a 30 caliber. Need some warmer weather to go further.

[Pisgah]

A friend brought me a Glenfield with the same problem. He shot it for years with no problems, then it started keyholing, despite the fact he was almost religious about cleaning. It looked fine, but I suspected copper fouling when he told me he had never used copper solvents -- too "damaging" to the bore, dontcha know.

I ran a patch wet with Sweet's 7.62 through the bore which came out a rich blue. He left it for me and I swear I must have cleaned it 100 times over a 2-week period before the patches came out clean -- but the problem went away.

[Charles]

When a bullet keyholes it is because the bullet is not being stablized in the barrel and the possible causes are;

1. Badly worn bore.
2. Undersized bullet (wrong caliber or cast bullet sized to small)
3. Rifle was made with an oversized barrel. I have one 1960 Marlin MG rifle in 30-30 that measures .307 X .310 land and groove. It was made that way. I have never fired a jacketed bullet load in the barrel only fire cast with bullets that fit those specs and get good results.

A bad crown will cause the rifle to shoot large groups, but not keyhole the bullet. At least, I have known of such. I have seen a rifle's groups open up 4 to 5 times the normal size due bad metal fouling in the barrel, but never to keyhole. I am not questioned the fact that it did in the related case about, but it would be rare for that to happen.

As always, when a friend comes to you with a problem, go shoot the rifle yourself. Sometimes people don't tell it straight and you end up like a dog chasing it's tail trying to run the problem down. Been thre, done that, and unless I shoot it myself or at least see the target, I won't try and diagnose the problem.

[Retro]

Also 4. Bullet too heavy.

But this is hardly likely in this specific instance.

My 357 Rossi doesn't like 190 grainers, they're going sideways at 25 yards.

But the Marlin is made to stabilise 150 and 170 grainers so... that's not the issue.

[jnyork]

As always, when a friend comes to you with a problem, go shoot the rifle yourself. Sometimes people don't tell it straight and you end up like a dog chasing it's tail trying to run the problem down. Been thre, done that, and unless I shoot it myself or at least see the target, I won't try and diagnose the problem.

Whole lot to be said for that!

[AJMD429]

Also 4. Bullet too heavy.

...or Bullet Too Slow...

If he hasn't tried several different loads, that's the easist next step...

[w30wcf]

Years ago a friend with a .30-30 Marlin made in the 1960's was having a problem with partial keyholing. He was using 150 gr ammunition but I don't remember the brand. I slugged the barrel and it measured .3085" in the grooves. I suggested he try 170 gr bullet ammo since it engages more of the rifling due to its longer length.

He happily told me that fixed the problem.

In another situation, another friend had a .32 Special Marlin that was keyholing. When I slugged the barrel I noticed that about 2" from exiting the muzzle there was no resistance at all. For whatever reason (cleaning rod wear?, etc.), the end of the barrel was oversized. We cut 2" from the end of the barrel and recrowned it.

No more keyholing!

w30wcf

[Irascible]

I agree with shooting it myself, but it's going to have to wait for a while. It's 9 degrees now and I'll want at least 40 before I go out and sit at the bench. Much to comfortable here by the woodstove. Good day for casting!

[sore shoulder]

Just when I get interested in the problem.

My 2 cents as far as what I know can cause this problem, fwiw.

Too heavy bullet/too slow of twist.

Bullet too small for bore.

The other comments regarding copper fouling are interesting, had no idea that could cause keyholing.

After reading some of the comments regarding slugging the bore and what was found by others, I'd say that's a good place to start, and you can do that by the fire!