Gunsmithing Pad or No Pad??

[Quackaddict]

To make a long story short, I have an SPS varmint action and stock bedded into a McM A5, the Gunsmith that did it put a pad of bedding the length of the chamber in front of the lug. It acts like it wants to shoot but all I can seem to get out of it is .75-1 Moa. I consulted with another smith and he said he would have done the same thing.

I am considering grinding out the pad to see if it will shoot better, the HS stocks bed just to the lug, all the talk on the internet is about fully free floated barrels to not mess with harmonics, am I wrong in this logic? Is 26 inches to much to hang off the action?

The Savage and the remmy I have access to are bedded just to the lug (in HS stocks) and they shoot better than this particular rifle.

 

[EZaccuracy]

Re: Pad or No Pad??

How far people bed in front of the lug is always a debate. Ive always done about and inch in front but I know there are gunsmiths who will bed as far as 3 inches ahead of the lug. There are a hundred reasons why the rifle isn't shooting as well as you think it should but go ahead and grind some away if you think its the problem. You can always put it back!

 

[Greg Langelius *]

Re: Pad or No Pad??

If you're using the same load as before, there's your problem. Change the bedding, and you change the barrel harmonics.

Redevelop your load.

<span style="font-style: italic">Don't</span> mess with the bedding.

Greg

 

[Sniperhandle]

Re: Pad or No Pad??

I prefer the pads for my lighter days!!

 

[sandwarrior]

Re: Pad or No Pad??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniperhandle</div><div class="ubbcode-body">I prefer the pads for my lighter days!!</div></div>

What about when ya get all crampy and bloated??

...

Seriously, if it was shooting better before, take out back to the recoil lug. But, before I did that, I would do like Greg says a try some load development. Keeping track of powder speeds and single/double base type powders. That's how you'll know what area your rifle likes best. Certain cartridges do tend to like the same speed ranges though, even when you can get more velocity from a slower powder.

FWIW, I've got great shooters that are barely bedded and others that shoot great that are bedded from the back of the action to 1/4 the way up the barrel.

I recommend two things when you bed a rifle.
1. You bed the rear and bottom of the recoil lug. The front of the recoil lug doesn't matter that much. It can keep the lug pushed up against the bedding to the rear of the recoil lug.
2. Make sure the action screws have zero play in them when you get done pillar bedding them. Torque alone can't hold them during stiff bouts of recoil if there isn't anything alongside them.

To me the bedding under the barrel doesn't mean as much. The accuracy there is attained by truing the action and barrel to each other, and tight tolerances on the threads.

 

[nashlaw]

Re: Pad or No Pad??

I bed mine about an inch in front of the lug. But I have had some rifles built by old school 'smiths that were full length bedded and shot great.

 

[Greg Langelius *]

Re: Pad or No Pad??

I do something oddball myself.

I bed up to the lug as normal. When it cures, I remove the action, and add several shims of bond paper between bedding and action. Before I replace and tighten the action screws, I apply RTV Silicone ahead of the lug, to about the length where the case shoulder extends.

As Silicone cures, it releases a mild acidic byproduct; and that acid can destroy any blueing it comes into contact with. So I first prep the metal surfaces with enamel and let it dry hard. Apply release agent on top of that.

Once everything is reassembled, tightened and cured; I remove the paper shims, then remove the enamel with thinner, and reassemble the rifle.

I personally believe the bedding under the chamber is useful, but because of barrel expansion, I prefer to use something that is more resilient than hard cured resin.

The paper shims, once removed, ensure that the silicone is under compression when the action screws are fully tightened. I'm not certain if or how that helps, but it seems to.

Greg

 

[Quackaddict]

Re: Pad or No Pad??

Lots of good info here, I wanted listen to the convo more than anything. I would like to clear a few things up thou.

I never did any load workup without the bedding in it, I only shot a few rounds to get a feel for the rifle.

I understand the SPS barrel is likley a crap shoot. I will eventually replace and true the action.

The gun shoots a ton of different loads into let than 1 inch at 100, but getting into the .5 range is inconsistent at best.

I have killed prarie dogs out to 625 ish with it, it shoots decent but I just am hoping to find that great load that will make em all touch.

 

[Greg Langelius *]

Re: Pad or No Pad??

Well, I'd still suggest load development before several other things, and only then, maybe mess with the bedding.

When working up a rifle, bedding is usually the first task I do. I then move on the optics and mounts, taking special care to ensure stability.

I don't think it makes real sense to try load development before nailing down at least those two factors; because until then, it may be difficult to equate inaccuracies solely to the load.

My best guess is that once those two preliminary factors are confirmed, your accuracy node will be found with load development.

As a final note, when you get down to about 1/2MOA, stop beating the horse. Going from 1MOA down to 1/2MAO is a reasonable project. Going from 1/2MOA down to, say 1/4MOA, usually isn't. That's where frustration and unrewarded excessive throat wear usually lurk.

Never underestimate a factory barrel. As long as they are in reasonably OK condition; load development, good bedding, and proper optics/mounts should get them at least down to the 1/2MOA mark. Despite some occasional literature to the contrary, I also believe a clean crown is essential.

Greg