Gunsmithing Stress on a Savage receiver

[Helidriver]

I'm in the middle of a Savage 6.5 Lapua build. I've decided to go with a 24"-26" Shilen bull barrel. Considering the weight of that barrel would adding a suppressor be too much stress on the action screws and receiver? I broke the head off a factory action screw tightening it to 55 in lbs a while back so I know they are weak to begin with. I've never heard this question come up before. My Cyclone will add 8.75 inches and 22oz to the barrel when I decide to use it.

 

[z71rat]

I wouldn't worry about stressing the receiver. However, I do recommend replacing the screws with some heavy stainless 1/4-28 hex head screws that are available at most hardware stores. Just cut to the proper distances, using your factory screws as a guide.

I have ALWAYS replaced my factory screws, just for my own piece of mind.

DK

 

[mscott]

I use a heavy form 1 can on a7mmRM with a 30" bull barrel and have noticed no issues. I don't have factory screws either.

 

[Helidriver]

Awesome. I'm going to pickup some stainless screws and call it good.

Sent from my SAMSUNG-SGH-I317 using Tapatalk

 

[Greg Langelius *]

Many years ago, I saw a blurb in a gunsmithing magazine which recommended 25 ln/lb as the proper torque value for the Savage receiver.

Whatever it is, problems with stock compression and/or action bolt breakage would seem to me a good indication that there's something wrong going on.

Greg

 

[anthonylapoint]

I had a 26" barrel that was .96 at the muzzle. This was mounted on a model 10. I torque to 60 and never had any issues with factory screws. Actually, it was the aluminum bedding block in a b&c that started to indent where's the screw heads were. Shot 1/4" 5 round groups any day of the week though

 

[Clark]

When I run the numbers, the limit of torque on action screws is almost always stripping out the female, not snapping off the male, so grade 5 bolts will not change the max tension.

OK, I am going to run the numbers.
The 1/4-28 has a minor diameter of
http://www.engineershandbook.com/Tables/threadlimits.htm
0.2062"
Feels like 3A threads to me [tight].

Engineers at Caterpillar use a standard that full engagement in steel is 1.0 to 1.2 times the root.
http://www.practicalmachinist.com/vb/general/tapped-thread-depth-strength-question-153783/

At 28 TPI = .0357"/turn, 1.0x the root would be .2062/.0357 = 5.77 turns
1.2x the root would be 6.93 Turns.

Looking at this 1976 Sav 110 I have apart here, I see 4 good grooves to engage in the tapped holes in the receiver.

Just as I suspected, the female is only 2/3 as good as the male.
The male in grade 5 would do 1200 pounds clamping
http://www.derose.net/steve/resources/engtables/bolts.html
So maybe the female can do 800 pounds.
The screws are 5" apart and it is 22" from the front screw to the muzzle.
With the front screw as the fulcrum and the rear screw in test, we could only expect 23% of the clamp force at the muzzle. => rate the muzzle attachment for 180 pounds.