Bent Barrel? Marlin 30-30

[SR5]

Hey all,
Brand new to NW Firearms so I apologize if I am posting this in the wrong place.

I have a 70s (?) Marlin 30-30 lever action that I recent inherited and have begun getting to know and have quickly have come to the conclusion that it shoots to the right consistently. The sights look very centered on the top of the rifle so I put a red dot on off another rifle to try another way to diagnosis and took it to the quarry. Attached is a photo of what im looking at that I could use some help understanding.

Shot #1 from 25yds, low and to the right - adjusted the optic up a handful of clicks.
Shot #2 from 25 yrds, higher but still to the right - left the optic here and started moving back
Shot #3 from 50 yards, bullet starts drifting further right
Shot #4 from 75 yards, bullet keeps drifting further right


From my understanding, there is no reason the bullet should be drifting further to the right on the x-axis given different shooting distances? I would love to get this rifle reliable but struggling to understand the problem before spending $$$ at a gun smith

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[P7M13]

You need

 

[fredball]

Welcome Aboard

 

[orygun]

Shot #1 from 25yds, low and to the right - adjusted the optic up a handful of clicks.
Shot #2 from 25 yrds, higher but still to the right - left the optic here and started moving back
Shot #3 from 50 yards, bullet starts drifting further right
Shot #4 from 75 yards, bullet keeps drifting further right
View attachment 2199176

From my understanding, there is no reason the bullet should be drifting further to the right on the x-axis given different shooting distances? I would love to get this rifle reliable but struggling to understand the problem before spending $$$ at a gun smith

Yes, there is a correlation to you moving the shooting position further from the target and the bullet heading further to the right. I highly doubt the barrel is bent, but more likely that the optic and the bore of the barrel aren't pointing in the same direction. If your sight is centered on the target, but the barrel is pointing to the right of that point, up close the bullet will only go a little to the right. But if you stretch that distance, the angle the bullet is travelling compared to the sight stays the same and the bullet continues to the right. Distance doesn't change the angle, it just makes it more obvious.
Go back and shoot up close again. Make your windage correction, or most of what's needed to put the bullet in the red, then move back and try again.

 

[roseburger]

Out of curiosity, it looks like you only changed the elevation on the dot. Is there a reason you didn't adjust windage?

 

[Pepe-lepew]

How far off is the iron sights shooting? They are mounted on the barrel so they should be close to adjusted when centered.

 

[Andy54Hawken]

it shoots to the right consistently. The sights look very centered on the top of the rifle

Is there any reason you can't gently tap the rear sight over to the left...?
( A brass drift pin or wood dowel works well for this purpose )
Andy

 

[Knobgoblin]

Before getting mechanically involved, try sending another half box of ammo downrange from a solid rest.

Bore sight would be a good idea too.

 

[GrayGoose]

View: https://youtu.be/aijBO7iKcnE?si=oCUiMV0TqJ-6d_cJ

 

[jbett98]

Amazon sells cartridge laser bore sights in 30/30 caliber for under $12.00.

 

[SR5]

Yes, there is a correlation to you moving the shooting position further from the target and the bullet heading further to the right. I highly doubt the barrel is bent, but more likely that the optic and the bore of the barrel aren't pointing in the same direction. If your sight is centered on the target, but the barrel is pointing to the right of that point, up close the bullet will only go a little to the right. But if you stretch that distance, the angle the bullet is travelling compared to the sight stays the same and the bullet continues to the right. Distance doesn't change the angle, it just makes it more obvious.
Go back and shoot up close again. Make your windage correction, or most of what's needed to put the bullet in the red, then move back and try again.

Okay, I think I am over thinking this and what you are saying makes sense as it will travel on the X axis if the angle is off. I'll go mess with it more today, Thanks!

 

[roseburger]

Okay, I think I am over thinking this and what you are saying makes sense as it will travel on the X axis if the angle is off. I'll go mess with it more today, Thanks!

Think about it this way. Stand facing a given direction and point you arm straight ahead. Now turn slightly. If you were to have two people walk in the given directions, they'll continue getting further apart. Same goes for your bullet, it doesn't make as big of a difference at close distances, but after an hour of walking, they'll be a long ways off.

 

[bcp]

Checking the barrel
---------------------------------
Remove the bolt from the rifle.

Place the rifle on a steady rest, maybe a box with a couple of notches cut in opposite sides.

Look through the bore. The near and far circles of the muzzle, bore, and chamber should be concentric.

Look through the bore at a vertical post, pole, doorway edge, etc. The reflection in the barrel should be straight.
============================

Checking the scope base and screw hole alignment
------------------------------------------
Hold a straightedge (yardstick, etc). alongside the base, out to the muzzle, and see where the edge is in relation to the muzzle. The do the same on the other side of the base. Both sides should be the same.

If not, check the screw holes. Remove the base. Insert screws into the front and rear scope base holes. Try the same alignment test as above.
================================

If you don't find a rifle problem, you have a sight problem.

If you do find a rifle problem, you have a good rifle to use with open sights only.

================================

Bruce

 

[Bobbygun]

Checking the barrel
---------------------------------
Remove the bolt from the rifle.

Place the rifle on a steady rest, maybe a box with a couple of notches cut in opposite sides.

Look through the bore. The near and far circles of the muzzle, bore, and chamber should be concentric.

Look through the bore at a vertical post, pole, doorway edge, etc. The reflection in the barrel should be straight.
============================

Checking the scope base and screw hole alignment
------------------------------------------
Hold a straightedge (yardstick, etc). alongside the base, out to the muzzle, and see where the edge is in relation to the muzzle. The do the same on the other side of the base. Both sides should be the same.

If not, check the screw holes. Remove the base. Insert screws into the front and rear scope base holes. Try the same alignment test as above.
================================

If you don't find a rifle problem, you have a sight problem.

If you do find a rifle problem, you have a good rifle to use with open sights only.

================================

Bruce

It's a lever action in the photo.

 

[bionic knees]

Amazon sells cartridge laser bore sights in 30/30 caliber for under $12.00.

View attachment 2199297

I bought one of these for my .270 wsm thinking it would be the ticket to easy sight in after changing scopes, boy was I wrong. it didn't work for me at all.

 

[Koda]

Those older Marlins are well built rifles, your barrels not bent... your rifle looks too nice to be that abused. The older ones without the crossbolt safety and gold trigger are worth something, hold onto this one. They are great guns and good shooters.

Regardless of sight system, to properly zero a rifle you need to shoot a group of at least 3 rounds at the same point of aim, from the same position, and same distance, and same ammo, and adjust zero from there. Repeat till the group is centered on bullseye. Zeroing rifles is best done from a benchrest or very solid stable shooting position, the Marlin should hold at least a 2in group at 100 yards with common factory ammo, or better at a closer range zero. They are commonly sighted in at 100yds, though 50 yards is ok depending on ones needs. I wouldn't zero at 25 yards personally. Zero distance depends on use, for general deer hunting Id zero at 100yds.

To adjust windage on the factory iron sights you might need to drift the front sight blade, it shouldn't take much. First check the sight base is solidly mounted to the barrel. You might also be able to drift the rear sight, or a combination of the two... but I don't recall if the 336 was designed to drift the rear sight to zero, only elevation. If the iron sights don't seem to get the rifle zeroed then maybe replace the rear sight assembly, maybe its bent or damaged over the years, same for the front sight since your rifle doesn't have the hood protecting it though Id imagine it would be hard to bend a front sight blade on those, its also possible the dovetail is worn and the front sight moves with recoil. If so replace the entire front sight assembly.
Optical sights are pretty self explanatory to zero, though proper mounting and torquing of the mounts is critical.

 

[bcp]

It's a lever action in the photo.

Marlin 336 bolts remove very easily.

See 1:40-2:30 in this video.

View: https://www.youtube.com/watch?v=sCdLzIGdK4s


Bruce

 

[Bobbygun]

Marlin 336 bolts remove very easily.

Bruce

Can you look down the barrel? (Other than from the business end.)

 

[Koda]

Can you look down the barrel? (Other than from the business end.)

Yes, very easily. The Marlins are great for this and why they became popular over their old Winchester top ejection counterpart. You can easily boresight a Marlin.

 

[Bobbygun]

Marlin 336 bolts remove very easily.

See 1:40-2:30 in this video.

View: https://www.youtube.com/watch?v=sCdLzIGdK4s


Bruce

Thanks for the video! Honestly, I thought you were thinking it was a bolt action rifle.

I've got an old Marlin model 93 I inherited from my grandfather. Well, actually he gave it to me a couple of years before he passed away. I've shot it sparingly but never considered attempting to remove the bolt. I would have figured that was work for a gunsmith. Now I'm curious.

Thanks again. (I'm never too old to learn. )