A semi-rhetorical question about barrel bedding


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mnealtx
January 5, 2003, 02:46 AM
My question is, for now, rhetorical - I hope to be buying a hunting rifle (most likely either one of the Savage Model 10 variants, a Rem 700, or a Win 70) in the fairly near future.

In Mr. Ching's information page about his new Safari Sling (looks like a GREAT product, Mr. Ching, and I hope to get one when/if I buy that hunting rifle) he mentions that sling pressure could interfere with point of impact with a weapon that is bedded with upward pressure at the tip of the forend.

Here's the question: If your rifle is bedded with forearm pressure and you use one of these slings, what problems would be involved with making it accurate and repeatable via free-floating?

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Robert inOregon
January 5, 2003, 04:20 AM
All the rage today is about free floating the barrel. Some of the newer super guns showing up at high power competition have free floating actions as well with the collar holding everything to the stock. Others use a type of sleeves on the barrel where it meets the action and use that point to mount to a stock. But the basic concept is the same. Barrel has to be free floating in order to optimize accuracy. With the barrel unattached to the stock, sling pressure is moot. All those rifles you mentioned have free floating barrels today.

mnealtx
January 6, 2003, 12:48 AM
Robert: I understand your point. I also understand that quite a lot of rifles need some upward pressure at the forend tip.

I guess I didn't phrase the question as clearly as I could have: If you have a rifle that is bedded with upward pressure, what difficulties would there be in free-floating the barrel? Would it even be possible to get the rifle shooting consistently, or would you end up changing the barrel?

Robert inOregon
January 6, 2003, 03:18 AM
Unless we're talking lever rifles, battle rifles or a derivatives of the two, no one makes a rifle with pressure points at the forearm. That tech is long gone in long range shooting. If a older rifle has this type of technology, it would need to be glass bedded and anchored to the stock at the receiver and barrel channel reshaped so that it does not make contact with the stock.

Robert inOregon
January 6, 2003, 03:25 AM
Modern rifles float. This is my twenty-two. Its a bit exaggerated, but demonstrates how far designers are willing to go and let the barrel hang out there by itself unmolested.

http://home.earthlink.net/~pkalfonso/ruger1022.jpg

Art Eatman
January 6, 2003, 06:15 AM
1. I think the Ching Sling is a heckuva Good Thing for offhand shooting.

2. If the forearm of a stock is not flimsy, modest pressure with the sling shouldn't affect the point of impact.

3. I only use my sling for carrying. :)

I prefer my stocks free-floated and then shimmed where about five pounds of pull is needed to separate barrel and stock to insert the shim. All this shim does is act as a damper of barrel vibrations.

So: If you find a load which harmonics properly with your barrel, you wouldn't need a shim. This is one reason the BOSS works so well; a free-floated barrel can be tuned and so the use of a sling won't affect anything.

Otherwise, sight in your rifle, and then see what happens to the Point of Impact when sling pressure is applied. If you change your scope to match the POI, you'll always have to apply the same pressure to the sling...

Art

Khornet
January 6, 2003, 08:03 AM
lesser quality barrels, and very slender barrels, don't do well with free-floating. Heavier/stiffer and high-quality barrels do their best floated.

Ruger's 77/22 has forend pressure. Many model 52s do also, though that's old technology.

mnealtx
January 8, 2003, 02:09 AM
Art - thank you, your post about the shim was what I was trying to describe.

I've looked at the Winchester site before, and have heard of the BOSS, but didn't see anything on the website about it - is it still even sold?

Let me try to restate it again, because I guess I'm still not being clear.

If I buy a rifle that needs to be shimmed to shoot to a consistent POI, what, if anything, could be done in regards to bedding/adjusting to make it consistent w/OUT the shim?

Anyone have any suggestions? As I said before, I'm looking at a Savage Model 10 mostly, but am considering Winchester Model 70 or Remington Model 700 as well.

Khornet
January 8, 2003, 06:57 AM
under the tang where the rear action screw goes through, and BEHIND but not touching the sides or bottom, of the recoil lug, and about the first 2" of barrel ahead of the action, wnd leave the barrel free enough that a matchbook cover can be slid under it. Then shoot, and if you like results, you're done. If not, put a dab of Acraglas under the barrel near the forend tip, clamp assembled rifle in padded vise upside down, and suspend about 5lb weight from the barrel right where it emerges from the forend and let the glass set. Then try it again. There are further ways to improve bedding, discussed in 'The Accurate Rifle' by Warren Page.

mnealtx
January 9, 2003, 02:43 AM
Thanks, Khornet.... when I finally get the rifle, I'll check that out.

Art Eatman
January 9, 2003, 10:07 AM
"...what, if anything, could be done in regards to bedding/adjusting to make it consistent w/OUT the shim?"

After bedding the action, and after the forearm is "hogged out" to a free-float condition, any remaining problems have to do with the barrel itself. Whether an inserted shim or a screw-in pressure point or Khornet's Acraglas dab, you're still fighting the barrel.

One solution which often works is to find or develop a load which harmonics "just right" with the barrel and gives consistent accuracy. As with many .22s, one particular brand of ammo in one or two weights of bullet will out-perform all others. In handloading, going up or down a half-grain by weight of powder or changing to either a bit slower or bit faster powder works.

To me, the wax-paper shim deal is the cheapest and simplest. Certainly cheaper than buying a custom barrel. :)

A BOSS can readily be added by a competent gunsmith. My problem there is that I don't like the appearance, but that's just my own notion of aesthetics.

Art

DMK
January 9, 2003, 10:58 AM
Art, the purpose of a shim for slight upward pressure is to dampen any inconsitent vibrations and tighten groups right?

That's definately a good thing. But, if (and that is a big if) using the shim allows a tight sling to inconsistently pull the point of impact over to one side, why not just remove the shim and allow the barrel to float completely?

Sure you'd open groups a bit, but at least point of aim and point of impact would be consistent.

Art Eatman
January 9, 2003, 01:15 PM
DMK: Yup. If you're gonna use a tight sling, I think you're better off if the barrel is not touching anything.

Anecdotal experience: Had a rifle that shot 2+ MOA. Free-floated it. Got down to 1 MOA, which I think is plenty good for 95% of all big game hunting. Shimmed it, and got down to about 1/2 MOA--but any variation in pressure on the forearm created problems.

Which gets us back to purpose and needs and, of course, the cost of something like a McMillan barrel...

Art

mark mcj
January 9, 2003, 10:46 PM
As Art has stated, shimimng the forend, is a good way to make some rifles shoot better.
I've seen many rifles that shot better getting the barrel off the stock, and no contact anywhere. Just shim under the recoil lug. But doing this can cause the back of the action to twist a few thousands.
I've also have floated skinny barrels and have had good results as long as the barrel doesn't warm. Good thing to look at if you get an older wood stock, skinny barreled hunting rifle if it won't hit consistently with a cold first shot.

just .02

mnealtx
January 10, 2003, 01:35 AM
Everyone,

Thank you for the replies. I guess that I'm flashing back to my days on JROTC Rifle team. We had a couple of rifles where, if your sling wasn't placed JUST right on your arm, would pull the POI off.

As I said, this is rhetorical for the moment, but I'm definitely planning to buy a .308 bolt action for hunting/plinking.

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