Bedding aluminum block stock

S

SEHunter

New member
I have a new HS Precision aluminum block stock that I'm planning to bed with Devcon. My plan is to only bed the recoil lug recess and just skim bed the block surface area where the action screws run through. Im only going to rough up the block surface in the center section for good adhesion of the Devcon then allow the action to rest on the block as it normally would where the thin lines normally show on the action from the block. I don't want to alter this area so I plan to not even rough up that isolated area.

This will handle eliminating front to rear movement (and most twisting via the lug being bedded) but the part I'm still concerned about and not clear on is working to further eliminate twisting by having the action screw passages bedded. I bought long bolts to cut the heads off that will be screwed into the action and used as my aligning pins then I want to work the Devcon down in the screw passages...

Because the action screw passages are larger in diameter than the 1/4" screws, I'm concerned about getting the action centered perfectly in the stock since the alignment pins won't have the beveled screw head like the original action screws have. What is the best way to ensure the action is centered while the Devcon cures? Is it possible to coat the original screws and action threads with release agent then remove the alignment pins and install them just to the point the beveled heads align the action perfectly? This sounds risky but i was wondering if doing this and backing out the screw and tightening it up every half hour or so for several hours would keep the Devcon from bonding to them? I would much appreciate any advise or instruction with this part of the process.
 
Put just a dab of bedding compound right behind the recoil lug. Nothing else. You do not want the recoil lug locked in place. You do not want the screws touching inside the holes. Don't overthink it, bedding blocks were made the way they are so you shouldn't have to bed them.
 
What you said about the action screws not contacting anything through the stock is music to my ears but if you would, please elaborate on your recommendation of not fully bedding the recoil lug. Much of my research and conversation about this may have revolved around wood or another type of non aluminum block stock without me realizing that but it seems that the idea of bedding the lug (with the sides, bottom and front face taped) and the first 1"-2" of the barrel is kind of a bare minimum, relatively speaking. I don't recall hearing a recommendation against it but again, I can't say for sure if any of these examples involved an aluminum bedded stock.

I understand that bedding the lug on most rifles is intended to in part reduce twist which is understood to be a threat toward accuracy. I have the stock on my bench and I've removed the barreled action (Remington 700) out of the old stock and removed the trigger assembly. When I test fit the barreled action in the stock, it has a generous amount of twist without the action screws in place which is why I originally thought bedding the action screws may benefit. Maybe the action screws themselves are enough to eliminate twist since they have the cone shaped heads? Please don't take offense to my question because I know you're an experienced and respected member on these boards and that's why I'm digging deeper into your reply specifically about not fully bedding the recoil lug recess.
 
The action screws will keep the action from twisting. The recoil lug keeps the action from moving to the rear in the stock when the rifle is fired. Contact on the sides and front of the lug cause binding and stress in the action as it expands due to the heat of firing and contracts due to cooling between shots. This also applies to putting bedding material under the chamber, don't do it.

Due to harmonics and vibrations when you fire the rifle, anything touching the stock will bounce the whole action away from the point of contact. Since the action is held in place, the "bounce" turns into vibrations which cause bullet dispersion.

Screws touching in the stock cause binding, which causes stress in the rifle during firing. You can split a wood stock in two if the screws touch inside the stock, or you can shear action screws. Neither is fun. You just want one point of contact (the action). Well, two, I guess, action and floor plate.

Years ago, some rifle builders would glue the actions into the stock in hopes of eliminating looseness and vibrations. They found was it makes rifles very temperamental due to the difference in contraction/expansion between the action and the stock materials with heating and cooling.
 
http://www.gun-tests.com/special_re...ing-Rifle-Stock-Brownells-Barrel-10952-1.html

If this link works, check out a few sections down where he discusses supporting barrels of #2 contour and smaller. I've not heard the center of gravity thing before. On my barreled action, it's literally half way between the muzzle and recoil lug and I wouldn't even think about that. If I bedded the first 2" or so of the barrel before the taper really drops off just to help support the action, you're saying it won't help or may hurt?
 
You can try it both ways if you're of a mind to tinker, but I will bet you will get better results without the bedding under the barrel. I used to put bedding under the barrel because I had read somewhere that you needed to support the barrel or its weight would destroy the thread on the action, then I figured out that if you put bedding under the chamber you are giving the weight of the barrel a fulcrum to act on the threads. I used to struggle to get rifles to perform consistently. When I quit putting bedding compound under the chamber area (where the most heat and shock occur), my rifles settled right down and shot.
 
Ok, that makes sense. I think I'll just start by assembling everything with no bedding and shoot it. If it's sub MOA then I'll leave it be, if not, I may experiment. Thanks for all your input.
 
I posted this in a related thread and wanted to include it in this one for any one that searches the topic with the same concerns...

"I made the decision to move forward with bedding my HS Precision stock. I had decided against it until I went to torque my action screws. Out of curiosity I torqued both the front and rear alone without the other one tight. When I did that with the rear action screw, it literally lifted the action away from the front mounting surface of the aluminum bedding block what appeared to be maybe 1/16" to 1/8". This was all the proof I needed to know my action would be stressed if I left it be.

This was just finger snug with a standard L shaped Allen wrench. Couldn't have been more than 20 inch pounds although I didn't check it. When I was curing the Devcon, I removed the line up bolts then applied release agent to the action screws. I barely snugged the front action screw and just allowed the rear screw to seat in place with no torque."
 
I never use stock/action screws when bedding.
Only headless studs, and surgical tubing wrapped tightly around the action from the recoil lug on back.
Torquing screws when bedding can induce the same stress in the receiver you're trying to avoid IMO.
 
You're right and I had this in mind the whole time I was contemplating my method. The ONLY reason I decided to put the screws in (well there are two but this is the main one) was because I was using the front of the original aluminum bedding block surface as my depth gauge instead of tape around the barrel like in a traditional action bedding job in a wooden or non aluminum block stock. In that case, you have no depth reference directly under the action. My semi novice logic was that it would be OK to apply minimum tightening to the front action screw to my dedicated anchor point as long as I did not tighten the rear action screw. I simply seated the rear screw in its recess to ensure the action was perfectly centered.

This was all when the Devcon was wet. I laid the action in the stock with headless 1/4" bolts but there was just a little play and I didn't trust that I had the action centered. That's why I backed them out and installed the screws. Within 20 minutes of that, I had snugged the front screw then backed it out until slight pressure was felt. Then I backed the rear screw out and seated it back in just to the point of contact and this is the condition it was in for curing. Theoretically there should be no binding here. It will be a learning experience. In hind sight, I may should have just bought a quality non aluminum block synthetic stock and just done a typical action bedding job. Next time around, I may do just that.

The concept of aluminum blocks is great but for the ultimate in precision, I just am not convinced that they have the hand in glove fit that a bedding job does. Guess we'll see. Either it will work or it won't. It's still sitting in my closet because I haven't had time to pull the action and clean it all up for final assembly. I'll report back after I get some range time in. Won't be too soon though with Christmas and all.
 
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