Pressure bedding

FirstFreedom · June 30, 2004, 06:35 PM

I have a CZ550 in .270 Win that I am going to have glass-bedded and "pressure-bedded". I'm going to take a Brownell's acra-glass kit to my gunsmith for glass bedding the action, as I would probably screw it up. My question is, for "pressure bedding" the barrel (i.e. it's going to be free-floated except for a small piece of material at the far end of the stock (inside) that will push up against the barrel, forming a consistent pressure, which I have read is better for thinnish/sporting barrels than a mere free-float) - so my question is, what commercial aftermarket part or kit has is available specifically for this purpose (if any). I need to supply my gunsmith with the part or he'll take 3 weeks ordering it. How would it work? Would it screw down into the meat of the stock with a screw or what? I want something solid and permanent that won't look crappy. I read about Art Eatman's wax paper pressure-bed technique, but that won't look so hot or be as permanent or satisfying to my mind as some piece of nylon, plastic, wood, or some such permanently attached, that conforms to the shape of the barrel and pressue beds in the way described. Does such a part exist in the aftermarket, or is it just as easy/desirable (or easier) to just fabricate the part and screw it in? It's such a simple part that I'll bet this is the case. But I'm placing an order anyway for a few things soon (somewhere), and if such a part is cheap, why not throw in on the pile, and save my gunsmith fabrication time? Also, what is the best material to absorb bbl vibration in the most consistent way to help accuracy? Thanks. (somewhat of a newb to serious riflery here).

JNewell · June 30, 2004, 09:41 PM

There are no parts to order -- it's best and most easily done with the glass bedding compound. If you are ordering things, be advised that the Brownells kits do not IMO include enough release agent.

Although there's no science and not much art to installing a pressure point at the tip, you really really really ought to shoot the rifle first and find out whether it's ok as is. Having said that, my recent experience with two relatively light barrels is that they were both happier with some pressure at the tip.

However, different rifles prefer different amounts of pressure. The rule of thumb is about 10# average, but that's like saying you should wear size 10 shoes because that's the average. If you're starting with a free-floated barrel, it's relatively easy to figure out what your rifle prefers using business cards or index cards as shims.

The best short discussion I've seen is in a book from the publishers of Precision Shooting entitled "Accurizing the Factory Rifle."

FirstFreedom · June 30, 2004, 10:32 PM

OK, thanks, that helps a LOT!

Gewehr98 · August 29, 2004, 12:10 AM

Why don't you glass-bed the action, and completely free-float the barrel to within an inch or so of the forward receiver ring? Pressure bedding with cardstock between the forend and barrel can be a dicey thing, you're basically trying to maintain a constant upward pressure on the barrel, regardless of temperature, humidity, and barrel harmonics. I'd recommend doing the glass bed routine, and if that doesn't settle the gun's groups down, then proceed to do the pressure point thing. That's an easy thing to do in an incremental fashion. I'm getting ready to do the same thing to a very early model Remington 700 BDL Custom, and I'm even routing out the barrel channel to afford more clearance. My last store-bought 700 VSS had a wooden hump in the barrel channel to act as a pressure point. It was gone within minutes, and the newly free-floated barrel found itself attached to a freshly Dev-Con bedded action.

JNewell · September 7, 2004, 02:30 PM

Just for clarity, I was suggesting cardstock only as an experimental expedient on an already-free floated barrel, to determine whether the rifle shot better with pressure at the forend tip -- not for permanent use.

Harry Bonar · February 19, 2005, 09:11 PM

Dear Sir:
I would have the recoil lug and rear tang area "glass bedded" ONLY.
Float that barrel all the way out! Use a thick business card to check, not a dollar bill since you'll be shooting off a bipod.
Harry B.

Harry Bonar · February 19, 2005, 09:13 PM

Dear Sir:
I would have the recoil lug and rear tang area "glass bedded" ONLY.
Float that barrel all the way out! Use a thick business card to check, not a dollar bill since you'll be shooting off a bipod.
Harry B.

Pardon me administrator, I apologize.

mete · February 19, 2005, 09:56 PM

There used to be a device on the market which was installed at the end of the forend and had two screws that you could adjust for pressure on the barrel.Like pressure bedding you had to play with it ....My own guns are all bedded the entire action plus two inches of the barrel , the rest of the barrel free floating .

Desert Dog · February 20, 2005, 11:57 AM

Quote:

If you are ordering things, be advised that the Brownells kits do not IMO include enough release agent.

Agreed. The solution? Saran Wrap. Works amazingly well. An old gunsmith friend of mine showed me that trick...

bill k · February 20, 2005, 12:23 PM

Suppose you have a heavy barrel which is free floated and the reciever is glass bedded already. Would the pressure bedding possibly help it also? It's in 22-250.

JNewell · February 20, 2005, 09:17 PM

With the caveat that rifles are as individual in their natures and preferences as people are, my experience leads to the generalization that heavy barrels do better free-floated, while thin lightweight barrels do better with some pressure at the forearm tip.

However, there are plenty of exceptions to every generalization. Try the business card-shim experiement. All it will cost you is a little time and a few rounds of ammo. If it doesn't work (and it may not), take 'em out and chuck 'em.

June 30, 2004, 06:35 PM	#1
FirstFreedom Junior member Join Date: May 31, 2004 Location: The Toll Road State, U.S.A. Posts: 12,451	Pressure bedding I have a CZ550 in .270 Win that I am going to have glass-bedded and "pressure-bedded". I'm going to take a Brownell's acra-glass kit to my gunsmith for glass bedding the action, as I would probably screw it up. My question is, for "pressure bedding" the barrel (i.e. it's going to be free-floated except for a small piece of material at the far end of the stock (inside) that will push up against the barrel, forming a consistent pressure, which I have read is better for thinnish/sporting barrels than a mere free-float) - so my question is, what commercial aftermarket part or kit has is available specifically for this purpose (if any). I need to supply my gunsmith with the part or he'll take 3 weeks ordering it. How would it work? Would it screw down into the meat of the stock with a screw or what? I want something solid and permanent that won't look crappy. I read about Art Eatman's wax paper pressure-bed technique, but that won't look so hot or be as permanent or satisfying to my mind as some piece of nylon, plastic, wood, or some such permanently attached, that conforms to the shape of the barrel and pressue beds in the way described. Does such a part exist in the aftermarket, or is it just as easy/desirable (or easier) to just fabricate the part and screw it in? It's such a simple part that I'll bet this is the case. But I'm placing an order anyway for a few things soon (somewhere), and if such a part is cheap, why not throw in on the pile, and save my gunsmith fabrication time? Also, what is the best material to absorb bbl vibration in the most consistent way to help accuracy? Thanks. (somewhat of a newb to serious riflery here).

August 29, 2004, 12:10 AM	#4
Gewehr98 Senior Member Join Date: July 1, 2000 Location: Token Creek, WI Posts: 4,067	Just a question... Why don't you glass-bed the action, and completely free-float the barrel to within an inch or so of the forward receiver ring? Pressure bedding with cardstock between the forend and barrel can be a dicey thing, you're basically trying to maintain a constant upward pressure on the barrel, regardless of temperature, humidity, and barrel harmonics. I'd recommend doing the glass bed routine, and if that doesn't settle the gun's groups down, then proceed to do the pressure point thing. That's an easy thing to do in an incremental fashion. I'm getting ready to do the same thing to a very early model Remington 700 BDL Custom, and I'm even routing out the barrel channel to afford more clearance. My last store-bought 700 VSS had a wooden hump in the barrel channel to act as a pressure point. It was gone within minutes, and the newly free-floated barrel found itself attached to a freshly Dev-Con bedded action.

February 19, 2005, 09:11 PM	#6
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	re-pressure bedding Dear Sir: I would have the recoil lug and rear tang area "glass bedded" ONLY. Float that barrel all the way out! Use a thick business card to check, not a dollar bill since you'll be shooting off a bipod. Harry B.

February 19, 2005, 09:13 PM	#7
Harry Bonar Senior Member Join Date: December 5, 2004 Location: In the Vincent, Ohio general area. Posts: 1,804	re-pressure bedding Dear Sir: I would have the recoil lug and rear tang area "glass bedded" ONLY. Float that barrel all the way out! Use a thick business card to check, not a dollar bill since you'll be shooting off a bipod. Harry B. Pardon me administrator, I apologize.

June 30, 2004, 09:41 PM	#2
JNewell Senior Member Join Date: March 12, 2000 Posts: 1,092	There are no parts to order -- it's best and most easily done with the glass bedding compound. If you are ordering things, be advised that the Brownells kits do not IMO include enough release agent. Although there's no science and not much art to installing a pressure point at the tip, you really really really ought to shoot the rifle first and find out whether it's ok as is. Having said that, my recent experience with two relatively light barrels is that they were both happier with some pressure at the tip. However, different rifles prefer different amounts of pressure. The rule of thumb is about 10# average, but that's like saying you should wear size 10 shoes because that's the average. If you're starting with a free-floated barrel, it's relatively easy to figure out what your rifle prefers using business cards or index cards as shims. The best short discussion I've seen is in a book from the publishers of Precision Shooting entitled "Accurizing the Factory Rifle."

June 30, 2004, 10:32 PM	#3
FirstFreedom Junior member Join Date: May 31, 2004 Location: The Toll Road State, U.S.A. Posts: 12,451	OK, thanks, that helps a LOT!

September 7, 2004, 02:30 PM	#5
JNewell Senior Member Join Date: March 12, 2000 Posts: 1,092	Just for clarity, I was suggesting cardstock only as an experimental expedient on an already-free floated barrel, to determine whether the rifle shot better with pressure at the forend tip -- not for permanent use.

February 19, 2005, 09:56 PM	#8
mete Senior Member Join Date: June 14, 2004 Location: NY State Posts: 6,575	There used to be a device on the market which was installed at the end of the forend and had two screws that you could adjust for pressure on the barrel.Like pressure bedding you had to play with it ....My own guns are all bedded the entire action plus two inches of the barrel , the rest of the barrel free floating .

February 20, 2005, 12:23 PM	#10
bill k Senior Member Join Date: December 9, 2004 Location: Dog Creek, CA Posts: 457	Suppose you have a heavy barrel which is free floated and the reciever is glass bedded already. Would the pressure bedding possibly help it also? It's in 22-250.

February 20, 2005, 09:17 PM	#11
JNewell Senior Member Join Date: March 12, 2000 Posts: 1,092	With the caveat that rifles are as individual in their natures and preferences as people are, my experience leads to the generalization that heavy barrels do better free-floated, while thin lightweight barrels do better with some pressure at the forearm tip. However, there are plenty of exceptions to every generalization. Try the business card-shim experiement. All it will cost you is a little time and a few rounds of ammo. If it doesn't work (and it may not), take 'em out and chuck 'em.