Gunsmithing Bedding Question

[tomcatfan]

After reading the extensive amount of info posted here on the subject, I recently have started messing around with bedding some of my rifles. I started with an old 700 chambered in .223 which was mounted in the old walnut stock. It is a really nice looking stock and the process went really smooth. I haven’t had a chance to shoot it yet, but I am under the impression that when when done right, bedding a wood stock should increase accuracy.

That leads me to my question. Bedding a stock can improve accuracy, but what if there is an aluminum bedding block already installed in the stock?

If you bed a Savage with an accustock, would you expect an acccuracy improvment? If you bed any stock with an aluminum bedding block, should you expect an accuracy increase? Has anyone bedded their savage accustocks and noticed an increase in accuracy? Has anyone bedded an HS or equivalent stock and gotten an accuracy increase?

It seems counter intuitive to me. In order to bed the stock you are going to have to remove some of the aluminum. It doesn’t make sense to remove aluminum and replace it with an epoxy. Could someone please shed some light on the subject. Thanks.

 

[Former0302]

Re: Bedding Question

Not a gunsmith, and this response is just based on reading and following directions in the excellent stickied thread at the top of this forum...but here's my understanding.

Aluminum bedding blocks will never be an exact mirror image of the receiver. Therefore, there will be some stress placed on the rifle in the firing process. How much? It depends on the receiver and bedding block match up. Real world answer...usually not all that much.

BUT, a proper bedding job ensures an exact mirror image of the receiver and therefore reduces as much stress from the rifle during the firing process as possible.

Will it improve accuracy? Depends on the rifle. I bedded a Rem 700 PSS in .223 following the instructions found here on the Hide and it didn't make much if any noticeable difference in the grouping. It was already a .75 - .5 MOA rifle. It did make a big difference in how smooth the bolt cycles.

Readers Digest version: Won't hurt it, might just help it.

 

[cooperjd]

Re: Bedding Question

im glad you posted this question, i'm sorry i can't answer it for you. i'm wondering the same thing, as i just ordred a b&c stock with the full length Al block, and was wondering if i need to skim bed the action to get that perfect fit.

 

[x ring accuracy]

Re: Bedding Question

Skim bed it.

 

[jasonZ]

Re: Bedding Question

Yep skim bed it. I can't say I noticed a big increase in accuracy, but there was some. However, the consistency of accuracy was well improved. It was good before, but after was much better. It would fluctuate from .4 (you know if I did my part) to .75. After it was pretty consistent to about .4 to .6 moa in general. Again there were off days, but I attribute that to me more then anything else. No it wasn't a great improvement, but it was an improvement. I also noticed that the bolt seemed to operate more smoothly and consistently than before as well. Good luck

 

[azimutha]

Re: Bedding Question

To me, part of accuracy is repeatability. Whether doing a full bedding job or a skim-bed on a v-block, the key is to think "stress-free". A factory receiver may be totally uniform and true but it might not. Likewise, with the v-block, although my parkerized LTR receiver had pretty uniform-looking wear lines along the action. Of course, that got me thinking: How is it that it's getting those lines. Seems it would be a slight amount of movement.

I fully bedded a Swiss K-31, which is a somewhat questionable thing to do because it actually relies on having a bit of stress on the barrel. However, it did shoot a bit better. I skim-bedded one H-S stock myself and another was done (accidentally) by a gunsmith before I got to it. Both rifles shot a slight bit better than before, which was .5 MOA with carefully prepared handloads.

Was it worth it? I then knew for sure that there were no stresses induced into the action and, by extension, the scope rail (although there could still be from an uneven surface on the action). Whenever I replaced the stock there was no question of it going back into exactly the same location. But it didn't halve my groups or anything as miraculous as that.

 

[wnroscoe]

Re: Bedding Question

Savage,

Years ago, concerning rifle building, I learned a lot from Speedy G. in Dallas when he was in business. One of the many things he said that always stuck in my head was this,

"Even if the stock has an aluminum chassis / bedding block and the receiver is torqued in, it's only a matter of time before it moves if you don’t bed it"

He was right, it did move eventually and accuracy suffered.

Yes, bed it but removal of the aluminum isn’t necessary.

 

[marksmatter]

Re: Bedding Question

There are differing opinions on whether you need to bed a stock with an Al chassis. I plan to bed mine - it makes the most sense to my simple mechanical engineer brain.

Even if (as some believe) there is no plus side, I cannot see a negative side.

 

[cooperjd]

Re: Bedding Question

ok, one further question for the skim bed camp.

since its aluminum, i wont be removing any material, so do i put any bedding compound near the rear tang area? or just around the action and up through the recoil lug?

thank you.
John

 

[BenY 2013]

Re: Bedding Question

I'm certainly not the expert but from everything I have read and experienced on savage rifles the tang should be floated. I tried to bed the tang on mine and it wouldn't group until I removed the material and floated it. Hope this helps.

 

[cooperjd]

Re: Bedding Question

thanks ben, one quick question for a newb to bedding. "floated" meaning it won't actually touch the aluminum block, but have a slight space underneath when the action screws are tightened down? that makes sense to me since the action will be sitting up slightly higher on the epoxy.

are there recommended torque specs for the stock screws? i think i saw 65 in/lbs somewhere as a starter number.

 

[marksmatter]

Re: Bedding Question

Same conclusion here - float the tang. It has to do with the location of the action screws on the Savage, I believe. I had to remove material from the B&C A2 in order to get a proper float. I think you can also fully bed the tang on a Savage (or is that only for 3 screw variants), but the tang bedding has to be a perfectly stress-free job or it can cause issues. Seems a lot easier to just float it.

 

[BenY 2013]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cooperjd</div><div class="ubbcode-body">thanks ben, one quick question for a newb to bedding. "floated" meaning it won't actually touch the aluminum block, but have a slight space underneath when the action screws are tightened down? that makes sense to me since the action will be sitting up slightly higher on the epoxy.

are there recommended torque specs for the stock screws? i think i saw 65 in/lbs somewhere as a starter number.</div></div>

Yes floating is when there is a space between the metal and the stock. I'm not sure what everyone else uses but I have seen people use dollar bills to test, if the bill will go between the tang and stock without resistance it should be good!

 

[tomcatfan]

Re: Bedding Question

I appologize for the dumb questions, but is "skim" bedding called skim bedding because you don't really put that much epoxy in the stock? I tried googling the issue and I couldn't find much on what skim bedding was. From what I did find was that you don't remove any of the aluminum, you simply rough up the aluminum block a bit to give the epoxy something to stick to. Then up a thin layer of epoxy in the stock to bed the action. Does this sound about right?

 

[300sniper]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body">There are differing opinions on whether you need to bed a stock with an Al chassis. I plan to bed mine - it makes the most sense to my simple mechanical engineer brain.

Even if (as some believe) there is no plus side, I cannot see a negative side. </div></div>

being a mechanical engineer, you should easily be able to come up with the axial friction force between the steel receiver and the anodized aluminum vee block being held together with two 1/4-28 screws torqued to 53 in lb. even without the recoil lug, it's pretty impressive.

needless to say, looking at those numbers, how every rifle i have built on an aics has shot, and how the other guys shooting our matches have shot with unbedded aics, i'm not sold on bedding them.

 

[glocksig40]

Re: Bedding Question

I think the biggest thing in the bedding is getting the recoil lug fitted tighter. Ive seen where the barreled action moves forward and aft slightly from recoil if the lug isnt bedded. This is even when the action screws are torqued properly. I see the paint on mine rubbing before they were bedded. Im sure this helps with accuracy insuring there is no movement. How much? who knows......

 

[Keith Johns]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Savage 10fp</div><div class="ubbcode-body">I appologize for the dumb questions, but is "skim" bedding called skim bedding because you don't really put that much epoxy in the stock? I tried googling the issue and I couldn't find much on what skim bedding was. From what I did find was that you don't remove any of the aluminum, you simply rough up the aluminum block a bit to give the epoxy something to stick to. Then up a thin layer of epoxy in the stock to bed the action. Does this sound about right? </div></div>

You got it.
I dont use the term "skim bedding" because I make sure there is a minimum thickness of epoxy to avoid cracking or chipping. In AICS's I dont mill away much material at all. I just rough it up and its still plenty thick.


To me, a "skim" bedding job would be if you took a perfectly(very tightly) inletted stock and used acra glass or something thinner than normal bedding to lay down a 1/32"thick or less coat of epoxy. This is done with high end wood stocks to seal them and strengthen them. The inlet is already perfectly fit to the action/barrel from hours of blood sweat and tears, so the epoxy in this case is <span style="font-weight: bold">not</span> serving the same purpose as a Tactical Rifle bed job.

 

[Keith Johns]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Savage 10fp</div><div class="ubbcode-body">It seems counter intuitive to me. In order to bed the stock you are going to have to remove some of the aluminum. It doesn’t make sense to remove aluminum and replace it with an epoxy. Could someone please shed some light on the subject. Thanks.
</div></div>

The point of epoxy bedding is to fit the action and lug like a glove.
The aluminum block does not do this. Far from it in fact.

Lug contact is often a problem with aluminum blocked stocks.

However, accuracy doesn't seem to be as greatly effected by poor lug contact with aluminum blocked stocks(as compared to fiberglass or wood).

I've seen a rifle shoot half MOA with zero lug contact in an AICS.
But does that mean its ok to have zero lug contact?
(in FamilyGuy mexican maid's lemon pledge voice....) "Nnooo"

 

[azimutha]

Re: Bedding Question

Like Keith says, you'll want to roughen up the surface. There is a little removal necessary, IMO, which is to create some mechanical locks for the bedding. I used a drill press to create several dozen 1/8" deep holes distributed across the action area and always as perpendicular to the surface as possible.

 

[marksmatter]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body">There are differing opinions on whether you need to bed a stock with an Al chassis. I plan to bed mine - it makes the most sense to my simple mechanical engineer brain.

Even if (as some believe) there is no plus side, I cannot see a negative side. </div></div>

being a mechanical engineer, you should easily be able to come up with the axial friction force between the steel receiver and the anodized aluminum vee block being held together with two 1/4-28 screws torqued to 53 in lb. even without the recoil lug, it's pretty impressive.

needless to say, looking at those numbers, how every rifle i have built on an aics has shot, and how the other guys shooting our matches have shot with unbedded aics, i'm not sold on bedding them. </div></div>

I'm not saying I'm 100% sold either on the necessity, but I just can't see any significant downside. I have other stock work to do also, so it's not a real big deal to just knock it out.

While I could determine the initial friction forces involved, I probably won't. After being out of school for 15 years, it'll probably be easier (and more fun) to just go ahead and bed. I enjoy doing new stuff.

To each their own.

 

[300sniper]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body">There are differing opinions on whether you need to bed a stock with an Al chassis. I plan to bed mine - it makes the most sense to my simple mechanical engineer brain.

Even if (as some believe) there is no plus side, I cannot see a negative side. </div></div>

being a mechanical engineer, you should easily be able to come up with the axial friction force between the steel receiver and the anodized aluminum vee block being held together with two 1/4-28 screws torqued to 53 in lb. even without the recoil lug, it's pretty impressive.

needless to say, looking at those numbers, how every rifle i have built on an aics has shot, and how the other guys shooting our matches have shot with unbedded aics, i'm not sold on bedding them. </div></div>

I'm not saying I'm 100% sold either on the necessity, but I just can't see any significant downside. I have other stock work to do also, so it's not a real big deal to just knock it out.

While I could determine the initial friction forces involved, I probably won't. After being out of school for 15 years, it'll probably be easier (and more fun) to just go ahead and bed. I enjoy doing new stuff.

To each their own. </div></div>

i guess since you brought up being a mechanical engineer as your reasoning for bedding an aics, i just assumed you would actually want to know <span style="font-style: italic">why</span> you are doing it. if you just enjoy doing stuff, i have no argument against that.

 

[marksmatter]

Re: Bedding Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: marksmatter</div><div class="ubbcode-body">There are differing opinions on whether you need to bed a stock with an Al chassis. I plan to bed mine - it makes the most sense to my simple mechanical engineer brain.

Even if (as some believe) there is no plus side, I cannot see a negative side. </div></div>

being a mechanical engineer, you should easily be able to come up with the axial friction force between the steel receiver and the anodized aluminum vee block being held together with two 1/4-28 screws torqued to 53 in lb. even without the recoil lug, it's pretty impressive.

needless to say, looking at those numbers, how every rifle i have built on an aics has shot, and how the other guys shooting our matches have shot with unbedded aics, i'm not sold on bedding them. </div></div>

I'm not saying I'm 100% sold either on the necessity, but I just can't see any significant downside. I have other stock work to do also, so it's not a real big deal to just knock it out.

While I could determine the initial friction forces involved, I probably won't. After being out of school for 15 years, it'll probably be easier (and more fun) to just go ahead and bed. I enjoy doing new stuff.

To each their own. </div></div>

i guess since you brought up being a mechanical engineer as your reasoning for bedding an aics, i just assumed you would actually want to know <span style="font-style: italic">why</span> you are doing it. if you just enjoy doing stuff, i have no argument against that. </div></div>

I never once mentioned an AICS. Don't believe that the OP did either.

My comment about being an engineer stemmed from another thread here on the same topic where mechanical engineering was brought up. I believe you participated in that one also. I'm knowledgeable enough in my field to have a valid <span style="font-style: italic"><span style="font-weight: bold">opinion</span></span> without having to mathematically model or prove it. I'd say you assumed incorrectly.

You don't like bedding on an AICS chassis...I get it. You like to argue...I get that too.