I recently bought my first bolt action rifle with a scope, a Marlin 25MN in 22 WMR with what I believe to be a Weaver style mounting rail. I have taken it to the range twice and both times after firing around 30/40 rounds the scope rings are sliding forward on the rail. I tightened the bolts on the rings as tight as I can get them but they are still shifting forward. So the question(s) is, are there different size scope rings for different rifles, or is there some trick that I'm not doing, or do the rings that the gun came with suck and need to be replaced?

After a few adjustments I had it shooting 1 1/2" groups at 100 yds., that is until the scope shifted.

22 minutes ago, gfl216 said:

I recently bought my first bolt action rifle with a scope, a Marlin 25MN in 22 WMR with what I believe to be a Weaver style mounting rail. I have taken it to the range twice and both times after firing around 30/40 rounds the scope rings are sliding forward on the rail. I tightened the bolts on the rings as tight as I can get them but they are still shifting forward. So the question(s) is, are there different size scope rings for different rifles, or is there some trick that I'm not doing, or do the rings that the gun came with suck and need to be replaced?

After a few adjustments I had it shooting 1 1/2" groups at 100 yds., that is until the scope shifted.

The scope is moving in the rings; correct?

I'm thinking it is the rings on the rail...

If that is the case, probably an aluminum rail/rings. Really, if try to upgrade the rail and rings. I know it isn't the best recommendation due to cost/time, but for the long run, better accuracy with a more secure mount.

And when you do remount them, blue Loctite and a torque driver. [emoji106]

There are lots of different types diameters and heights for scope rings. Look up your scope diameter to match up to the rings and then the right height so the bolt handle clears and you should be good

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assuming you don't have a mismatch in ring size vs scope diameter as mentioned, i'll regale you with some hands on experience...

for my $$ rifles, i use nightforce extreme duty ultralight mounts. for my money they are the best scope mounts in the world. for those, i don't use loctite at all. just mount, balance, torque to spec and it lives on the rifle forever.

last winter i thought i'd buy a ruger 10/22 just for the hell of it. it comes with what looked like a pretty nice weaver mount section. being unfamiliar with this weaver nonsense, i bought a cheap utg picatinny rail mount and a cheap set of warne rings. installed the utg mount and did the usual mounting ritual, also sans loctite. took it to the range to zero and after no more than 30 or so rounds, the scope (vortex) literally falls off of the rifle onto the ground. the utg rail mount had come off of the 10/22 completely. picked up the scope and found that the rings were loose as well. 

took everything home, re-mounted to the same proper torque, but this time i used blue loctite on everything. let it cure for 24 hrs and went back to the range to zero once again. this time i got about 50 or so rounds in when i noticed the scope was just flopping around on top of the rifle. it didn't come completely off this time, but both the utg mount and the rings were loose as hell.

really frustrated, i tossed both the utg mount and rings and re-installed the weaver mount the rifle came with (using loctite). then i bought some much nicer vortex rings (probably double the warne ones, but still in the $50 range), mounted everything and haven't had an issue since

moral of the story is: go cheap on dates and fast food. spend money on scope mounts. also read the installation instructions carefully for proper torque values and to see whether or not loctite is recommended. i've found that it's called for on the less expensive stuff, but the nightforces, geisseles, spuhrs, and badgers of the world say no, just torque the bare screws to spec. ymmv

6 hours ago, Zeke said:

The scope is moving in the rings; correct?

The scope is secure in the rings. The actual rings are what's moving. The mounting rail is the one that is one the receiver.

Few different options...

http://www.diproductsinc.com/Products.aspx?CAT=4803

15 hours ago, gfl216 said:

I recently bought my first bolt action rifle with a scope, a Marlin 25MN in 22 WMR with what I believe to be a Weaver style mounting rail. I have taken it to the range twice and both times after firing around 30/40 rounds the scope rings are sliding forward on the rail. I tightened the bolts on the rings as tight as I can get them but they are still shifting forward. So the question(s) is, are there different size scope rings for different rifles, or is there some trick that I'm not doing, or do the rings that the gun came with suck and need to be replaced?

After a few adjustments I had it shooting 1 1/2" groups at 100 yds., that is until the scope shifted.

Does your Marlin 25MN have a 3/8" dovetail groove on the receiver? 

I think I am running into the same issue, any recommendations on a torque driver?

Home Depot....  Husky torque screwdriver....$60.00

 

Pick up a tube of BLUE loktite if you don't already have some on hand. 

Many bolt action 22lr rifles have a 3/8ths dovetail scope mount milled into the receiver.  The Marlin 25/25N/25MN all have the dovetail.  Some 22 rifles, like my Marlin 39D, are tapped to mount an optional dovetail rail.

3/8ths dovetail mounts and rings are usually referred to as rimfire or air rifle mounts and rings as they are the only rifles that still use that type of mount.  Weaver and Picatinny mounts can be found on newer 22s, especially on semi-autos, but also on newer 22 bolt guns like the Ruger American rimfire..  Do not confuse the newer style mounts with classic dovetails.

 

Here is a link to Midway USA's rimfire and air rifle scope rings.

https://www.midwayusa.com/rimfire-and-airgun/br?cid=8589

 

1 hour ago, tomk62 said:

I think I am running into the same issue, any recommendations on a torque driver?

I've owned this torque driver for some time and have had no complaints so far. Also, don't forget to use a level.

FAT Torque Wrench

Scope Level

Regards,

TokenEntry

5 hours ago, Parker said:

Does your Marlin 25MN have a 3/8" dovetail groove on the receiver? 

This

4 hours ago, Scorpio64 said:

Many bolt action 22lr rifles have a 3/8ths dovetail scope mount milled into the receiver.  The Marlin 25/25N/25MN all have the dovetail.  Some 22 rifles, like my Marlin 39D, are tapped to mount an optional dovetail rail.

3/8ths dovetail mounts and rings are usually referred to as rimfire or air rifle mounts and rings as they are the only rifles that still use that type of mount.  Weaver and Picatinny mounts can be found on newer 22s, especially on semi-autos, but also on newer 22 bolt guns like the Ruger American rimfire..  Do not confuse the newer style mounts with classic dovetails.

 

Here is a link to Midway USA's rimfire and air rifle scope rings.

https://www.midwayusa.com/rimfire-and-airgun/br?cid=8589

 

This

5 hours ago, Scorpio64 said:

Weaver and Picatinny mounts can be found on newer 22s, especially on semi-autos, but also on newer 22 bolt guns like the Ruger American rimfire.

Oops.  My bad.  Apparently Ruger went with the classic dovetail on the RA Rimfires.  A trivial detail to the OP but incorrect none the less.  However, this raises an opportunity to bring up another point.  Their Target model comes with a factory installed Picatinny mount that slips over the 3/8ths dovetail.  So, if you have a drawer full of Picatinny style rings, you can always get a dovetail to picatinny adapter.  The only caveat is that it will raise your scope by about 1/2 MOA, depending on the thickness of the adapter.  If you are using a scope with a big honking objective bell, it wont matter much.

Redfield made a robust, all-steel mount/ring for these dovetails. I still have a set mounted on a .22 after almost four decades. Leupold &  Warne both make rings for this configuration. 

 

 

12 hours ago, Parker said:

Does your Marlin 25MN have a 3/8" dovetail groove on the receiver? 

Yes! It is a 3/8" dovetail groove that is milled into the into the receiver.

Thank you Parker and Zeke for finding the words that I was looking for. lol

Now that we know what we are up against, there have been a few responses with possible solutions. What do you guys think the best way to go would be for a guy on a budget?

On 9/6/2017 at 10:35 AM, TokenEntry said:

I've owned this torque driver for some time and have had no complaints so far. Also, don't forget to use a level.

FAT Torque Wrench

Scope Level

Regards,

TokenEntry

Thanks, I stopped in at Garden State Armory last night and they said the same thing.  I have one ordered.