2nd time scope has come loose on my ruger american 450 bushmaster...need help!

[Tripplebeards]

There’s not that much mark up in guns or optics. It’s like a gas station. No money in fuel so their hoping you come in for beer, soda, and candy bars. Or like going in for an oil change and getting talked into all your fluid flushes and an alignment. Gotta keep the lights on and employees paid.

[egg250]

Just took it apart. The factory picatinny rail is held on by four screws. The one closest to the bolt was finger loose! They are getting lock tited as we speak. I called al’s gun shop in Michigan who came up with this chambering in the Ruger American and said the RAR in 450BM are notorious for that screw coming loose and having the issues I’ve had. Hard to believe when the other three were rock solid tight.

I can see where that loose screw would lead to accuracy issues and, possibly, damaging your optics. Could you see where the scope was slipping in the ring mounts? Would you post a follow up as to repairing that loose screw solved the problem?

[Tripplebeards]

It’s sticks out like a sore thumb because of the Rosen I used. Like I said I even tightened down the ring screws after I noticed it at the range to the point I would have stripped or snapped them if I tourqued them any harder and the optic still continued to slide backwards. I might have pics in some of my old posts with the other optic that slid back and cut a huge ring in front bell and granaded the internals.


Here’s a pic of the front and rear with leupold PWR rings. You can clearly see the rosin dust and that it did not help hold it in place.







The more I look at the wear from the picatinny rail I have a feeling the only place it came in contact with on the receiver is were it wore off the bluing. The witness marks on the receiver is telling me it the only place it comes in contact with the picatinny rail. IMO it was barely contacting the receiver mating surface casing it to vibrate loose. Definitely needs bedding.

[Hickory]

3M makes a double stick tape (sticky on both sides) that has worked real well for me and can be removed with Goop.

[Tripplebeards]

When rifle comes back I’ll acraglass the base to the action, use blue lock tite on the screws in the base and scope rings, and spray 3M 77 super adhesive to the inside of the scope rings and let them dry for a few minutes before assembly. I’ll be shocked if it comes loose after doing this. I swear there is a Teflon type coating Nikon puts on it optics causing the slippage. They are the only optic I have had slide loose consistently on other firearms as well.

Here’s a pic of the front of the receiver where the picatinny rail wore off the bluing off the outside where it clamped to. I believe the whole picatinny rail was probably hovering above the mounting holes and just touching/ resting on the outside of the receiver. Not enough mating surface to keep it still.

[cwlongshot]

I cannot tell you the number of rifles I have “fixed” bu simply removing the base, cleaning the wcrews and holes!! If I am able Ill also check the bases to the action by lapping them to the top of the receiver. Then ince everything is clean and dry RED LOC TITING the bases to the gun.

Warne steel rings are top shelf. Leupold PRW, are pretty good but not as good as the Warne product.

I have over 500 thru my own RARR and no problems using factory base and warne rings and a leupold VXII 2x7 scope.

Good luck!!

CW

[Tripplebeards]

I have red lock tite as well. Acraglass or red lock tite? Is one better than the other? I would assume acraglass since it will fill in the high areas. I’d rather use the warne rings but dont see how I’m going to get the optic to slide back and forth along with left to right to adjust it to my eye once I spray the 3M in the rings.

[egg250]

Seeing is believing. With all that vibration, I'm surprised the scope wasn't shaken apart. You could use a bedding compound on the rail. You could also lap the rail into the receiver. Is the rail aluminum or steel? There'd be a slight bit of touch up finishing on the metal. Also, check to ensure the rail mounting screws are not bottoming in the holes.

Thanks for the pics.

[Tripplebeards]

The first scope was...and wrecked. I’m going to bed the rail to the receiver when it comes back. I plan on calling Ruger when they get it to see if they have a rail that will mate better to the receiver so I don’t have such a variance. I’ve lapped scope rings many of times but never a rail to a receiver. How is it done? I would assume bedding/gluing it with acraglass is going to hold it rock solid and never move when the process is done and being literally welded in place with the acraglass gel is going to be a more solid fit anyways.

[egg250]

The first scope was...and wrecked. I’m going to bed the rail to the receiver when it comes back. I plan on calling Ruger when they get it to see if they have a rail that will mate better to the receiver so I don’t have such a variance. I’ve lapped scope rings many of times but never a rail to a receiver. How is it done? I would assume bedding/gluing it with acraglass is going to hold it rock solid and never move when the process is done and being literally welded in place with the acraglass gel is going to be a more solid fit anyways.

If the rail is aluminum, I wouldn't bother to lap it. Bed it with epoxy, Loctite or other bedding compound. If the rail is steel, put some lapping compound on the rail and mounting area of the receiver, and move back and forth. Only move about 1/4" so as to limit the area that will need a finish touch up. If the receiver is blued, lapping could be an idea. If parkerized or coated, I wouldn't bother, just bed it.

[Black Powder Bill]

When rifle comes back I’ll acraglass the base to the action, use blue lock tite on the screws in the base and scope rings, and spray 3M 77 super adhesive to the inside of the scope rings and let them dry for a few minutes before assembly. I’ll be shocked if it comes loose after doing this. I swear there is a Teflon type coating Nikon puts on it optics causing the slippage. They are the only optic I have had slide loose consistently on other firearms as well.

Here’s a pic of the front of the receiver where the picatinny rail wore off the bluing off the outside where it clamped to. I believe the whole picatinny rail was probably hovering above the mounting holes and just touching/ resting on the outside of the receiver. Not enough mating surface to keep it still.

I take my bases including tang sight base and lay a piece of light wet dry,[pick a grit that looks good not to aggressive]; over the tang or barrel sand side up. Then take the base and slide it back & forth getting the shaped bottom area as close the curve of the barrel, receiver,tang as possible.
Thus creating a greater contact surface. Then everything gets a light coat of loctite to help keep moisture out just prior to screwing the base down. I let that dry for a day. Then I mount the scope.
If , yea usually the rigs need a bit of lapping as well. Clover make a good lapping compound. Or ask your dentist for some fine pumice grit. Mix it with some light oil or grease and lap gently with a rod of proper size.

If all else fails ad another ring to increase friction.

[cwlongshot]

Lock tite for threads. I always use RED on the bases, rarely even lock imtite my rings. No problems.

Last guns I had problems with where my Contenders. I literally sheared off the screws on my 14” 357 Herrett! Upped the screws to #8’s and THEY LOOSENED!! I REALLY THINK i didnt get the holes clean enough. And its. ERY IMPORTANT as oil will act like a release agent and DEFEAT the loctite.
I scuffed the bottom of the base and the top of the barrel and with new screws, accra glassed the base to the barrel AND red locktited it down!! No more issues.

Rubber Cement is simple and easy and most always works. BUT know you need to degrease parts!

Lastly, dot. Rush things! Give/Allow solid 24/48 hrs before use. Longer is BETTER!

I agree, its a problem gun/caliber. Invest in steel base to go with your steel rings.

Good luck!

CW

[CJR]

Tripplebeards,

I had a similar problem with a 375H&H Mag. My original steel scope mount was only a 3-screw and not in complete contact with the receiver. I replaced that mount with a 4-screw Picatinny rail and lapped the Picatinny rail to the receiver so I had complete rail/receiver contact. Steel Picatinny rails are three times stiffer than aluminium Picatinny rails; in other words an aluminium Picatinny rail will deflect three times more than a steel Picatinny rail for the same applied load. During recoil, a receiver bends: the heavier the recoil the more the receiver bends. Therefore using a steel Picatinny rail serves to stiffen the receiver against recoil induced bending. Another option I've used is to increase the size of the screws which in turn increases the clamping force that holds the Picatinny rail to the receiver and prevents any yielding from small screws. Obviously, lapping the rings to increase contact area, between scope tube/rings also helps. And as others have mentioned, adding another scope ring or two helps prevent the scope tube from sliding in the rings but typically does not prevent the receiver from flexing. However in my view, the flexing receiver under heavy recoil is the biggest culprit for loosening screws and/or scope movement/bending. Once you minimize receiver flexing; the screw loosening and scope movement/bending are also minimized.

Best regards,

CJR

[Tripplebeards]

It’s at Ruger right now. I asked them to remove the picatinny rail and inspect for rail damage and fitment while it’s there for loose trigger housing issues as well. Hopefully they’ll replace it with a more flush fitting rail that will need less bedding when I get it back.

[Tripplebeards]

It’s on its way back already! 24 hour turnaround time! They replaced the trigger housing per goodwill even though I polished my trigger per good will. I talked with the smith that replaced it and he said someone diberately hogged out the holes in my triggers housing. I told him I polished the trigger and cut the spring down a coil or two but never removed the trigger housing. I did tell him my action screws came loose from the rail vibrations and IMO probably rocked the trigger holes. He was extremely nice about it. In his original notes when I talked to accustomer service rep said the base screws were like a car and an oil change. It’s maintenance and I was responsible for checking them every so often. I explained that my optic came loose after the first shooting session so the oil change was done right before the car left the factory. We both laughed it off. I did tell him I will bed the rail and lick tite the screws when it comes back because I’m not going to remove my optic every 12 shots to check my base screws and relight it in. He also said that’s the way the rails fit (crappy) but is also sending along the new, long updated picatinny rail also per goodwill that he said is of stronger construction so I can tighten the rings down with more pressure. They tested it with factory Hornady 250 ftx rounds and said it shot one big hole with four shots measuring and outside to outside diameter 3/4” group. He also said the gun/caliber has been wrecking a lot of scopes things have been rattling loose. He suggested to switch to a shotgun scope since their set up to take more recoil. When it comes back I will bed the new rail and scope to the rings, polish the new trigger and remove a coil or two, retest, and report back and let everyone one know if things stayed put. I’d like to add a 3rd or 4th ring to the rail as well if anyone has an extra leupold PRW low or warne medium ring laying around PM me.

[cwlongshot]

Ruger has been good like that for me as well!

Service like that is good business. Things happen, good service mends many fences.

Glad to hear!

CW

[Tripplebeards]

The big thing that’s sticks in my mind is the Ruger tech/smith told me the 450 bushmaster Ruger American is not made for a target rifle to go out and shoot but just as a hunting rifle? I would assume he meant they weren’t designed well enough to hold together like the issues I’m having where it’s rattling a part. Guess they need to go back to the drawing board to design a stouter platform for this caliber.

[redhawk0]

That's an interesting comment. It could be that with such a high recoil it does't do well shooting from a "solid" sled. If shot from the shoulder only your body takes up some of that recoil...meaning it isn't all transferred into the scope/mounts...like on a sled.

Did you ever shoot the original setup (before sending it back) from the bench without the sled? Did you notice the same scope shift?

redhawk

[Geezer in NH]

Double stick tape in rings , lock tight the screws

[Tripplebeards]

That's an interesting comment. It could be that with such a high recoil it does't do well shooting from a "solid" sled. If shot from the shoulder only your body takes up some of that recoil...meaning it isn't all transferred into the scope/mounts...like on a sled.

Did you ever shoot the original setup (before sending it back) from the bench without the sled? Did you notice the same scope shift?

redhawk

No I didn’t but found the base screw loose so would have moved reguardless.