Free floating rimfire

cptmclark · May 7, 2006, 01:25 PM

Has anyone freefloated the CZ 452? What results? I have a surprisingly accurate one that I would never mess with, except the zero wanders. Just a little, well less than an inch at 50 yards. I can't tell what's causing it. Scope, rings, and bedding pressure seem OK. The barrel is floated except for the tip, where there is substantial pressure. I've never had a bad experience floating centerfire rifles, but uncertain about these. Thanks

cntryboy1289 · May 7, 2006, 10:27 PM

If you want to try to free float it, go ahead. If the gun doesn't shoot better with the free float, you can always rebed it properly with the correct upward pressure. I would completely bed the receiver and then sand the forearm area out to completely free float it first off. Then try it out to see if it improves for you. If this works, job is done and go enjoy.

If it doesn't, simply apply bedding back to the forearm tip, place the gun back in the stock, roll it over and place it in a padded vise and hang about a five lb weight from the barrel. Allow this to set up and completely harden. Go back and shoot the gun and see if you have it where you want it. If it isn't, simply apply more bedding material, and add more weight and repeat the process. Doing it like this, you can dial it in to where you want it. It might take you a few weeks to get it completed like this, but the end result will be that you have dialed in the bedding to what the gun likes.

Best of luck with it. I just bought my son one to use in his 4H shoots. He came in first with an older semiauto last weekend, but I think he needs to learn to slow down some more so I bought the CZ452 Varmint rifle. So far this one acts like it needs a complete new bedding job on it. After about 30 shots with it, it started walking as well.

**Unclenick** · May 8, 2006, 12:06 AM

Ditto CB's comments. Remington also used an upward pressure from the stock in their 600's. There is a version of this technique described in Harold Vaughns book, Rifle Accuracy Facts, he calls O'Conner bedding. It uses two pressure points 120 degrees apart with 10-20 pounds of upward pressure. Many Garand and M14 rebuilders use up to 50 lbs of stock pressure, but in their case it is downward pressure, made possible by how these rifles go together. Best pressure depends on the gun.

If you float the barrel and find it still drifts after a number of shots, bed it in the stock at the action, leaving the barrel floating. If it still persists in drifting as it warms up, consider sending it for cryo stress relieving. A floating barrel on a bedded action that drifts with temperature either is bored off the outside contour axis or has unrelieved assymetrical stress. You can check the former condition by spining the barrel between centers made by running 1/4" wood dowels into a pencil sharpener. One dowel goes in the muzzle end and one into the chamber. By doing the spinning with the gun vertical, it is easy to see whether the contour runs out in just a couple of turns (about as long as the dowel tips last).

Once you have the gun shooting so it doesn't drift on warm-up in the floating configuration, you can try out finding the best spot for barrel pressure by finding a thick cord that snugs between the stock and the barrel. Coarse twine usually works, but parachute cord may be needed if the gap is big. You start with it at the tip of the stock. Shoot a group with the ammo you most want to use for accuracy; the ammo that shot best when the barrel was floating. Then move the string back an eighth of an inch and shoot another group. keep this up until you find a spots where the pressure makes the groups smallest. That is where you want to put the bedding. Proceed as CB described.

Nick

aminyard · May 24, 2006, 01:40 PM

I bedded my CZ with Acraglas and free floated the barrel. After some trigger work I can now shoot (off the bench) 5 shot groups about .330 center to center at 50 yards. I call that acceptable accuracy

tINY · May 24, 2006, 01:50 PM

Doesn't that have a wood stock?

If it does, a slight wander like that is pretty normal, unless you don't have any weather where you are at.....

-tINY

cntryboy1289 · May 24, 2006, 04:52 PM

I think he was meaning that it wanders on him while shooting which indicates either a stress problem in the barrel or a bedding issue. Even with weather conditions that we have down south, the POI shouldn't be shifting on you while you are shooting. You can solve a lot shifting problems by bedding the rifle correctly and free floating the barrel is one of the first steps.

May 7, 2006, 01:25 PM	#1
cptmclark Senior Member Join Date: November 22, 2004 Location: Indiana Posts: 432	Free floating rimfire Has anyone freefloated the CZ 452? What results? I have a surprisingly accurate one that I would never mess with, except the zero wanders. Just a little, well less than an inch at 50 yards. I can't tell what's causing it. Scope, rings, and bedding pressure seem OK. The barrel is floated except for the tip, where there is substantial pressure. I've never had a bad experience floating centerfire rifles, but uncertain about these. Thanks

May 7, 2006, 10:27 PM	#2
cntryboy1289 Senior Member Join Date: July 19, 2004 Location: Ms Posts: 1,160	no problem If you want to try to free float it, go ahead. If the gun doesn't shoot better with the free float, you can always rebed it properly with the correct upward pressure. I would completely bed the receiver and then sand the forearm area out to completely free float it first off. Then try it out to see if it improves for you. If this works, job is done and go enjoy. If it doesn't, simply apply bedding back to the forearm tip, place the gun back in the stock, roll it over and place it in a padded vise and hang about a five lb weight from the barrel. Allow this to set up and completely harden. Go back and shoot the gun and see if you have it where you want it. If it isn't, simply apply more bedding material, and add more weight and repeat the process. Doing it like this, you can dial it in to where you want it. It might take you a few weeks to get it completed like this, but the end result will be that you have dialed in the bedding to what the gun likes. Best of luck with it. I just bought my son one to use in his 4H shoots. He came in first with an older semiauto last weekend, but I think he needs to learn to slow down some more so I bought the CZ452 Varmint rifle. So far this one acts like it needs a complete new bedding job on it. After about 30 shots with it, it started walking as well.

May 8, 2006, 12:06 AM	#3
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	Ditto CB's comments. Remington also used an upward pressure from the stock in their 600's. There is a version of this technique described in Harold Vaughns book, Rifle Accuracy Facts, he calls O'Conner bedding. It uses two pressure points 120 degrees apart with 10-20 pounds of upward pressure. Many Garand and M14 rebuilders use up to 50 lbs of stock pressure, but in their case it is downward pressure, made possible by how these rifles go together. Best pressure depends on the gun. If you float the barrel and find it still drifts after a number of shots, bed it in the stock at the action, leaving the barrel floating. If it still persists in drifting as it warms up, consider sending it for cryo stress relieving. A floating barrel on a bedded action that drifts with temperature either is bored off the outside contour axis or has unrelieved assymetrical stress. You can check the former condition by spining the barrel between centers made by running 1/4" wood dowels into a pencil sharpener. One dowel goes in the muzzle end and one into the chamber. By doing the spinning with the gun vertical, it is easy to see whether the contour runs out in just a couple of turns (about as long as the dowel tips last). Once you have the gun shooting so it doesn't drift on warm-up in the floating configuration, you can try out finding the best spot for barrel pressure by finding a thick cord that snugs between the stock and the barrel. Coarse twine usually works, but parachute cord may be needed if the gap is big. You start with it at the tip of the stock. Shoot a group with the ammo you most want to use for accuracy; the ammo that shot best when the barrel was floating. Then move the string back an eighth of an inch and shoot another group. keep this up until you find a spots where the pressure makes the groups smallest. That is where you want to put the bedding. Proceed as CB described. Nick __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

May 24, 2006, 01:40 PM	#4
aminyard Member Join Date: June 28, 2004 Posts: 60	I bedded my CZ with Acraglas and free floated the barrel. After some trigger work I can now shoot (off the bench) 5 shot groups about .330 center to center at 50 yards. I call that acceptable accuracy __________________ Guns don't kill people, husbands that come home early kill people. Al

May 24, 2006, 04:52 PM	#6
cntryboy1289 Senior Member Join Date: July 19, 2004 Location: Ms Posts: 1,160	hmmm I think he was meaning that it wanders on him while shooting which indicates either a stress problem in the barrel or a bedding issue. Even with weather conditions that we have down south, the POI shouldn't be shifting on you while you are shooting. You can solve a lot shifting problems by bedding the rifle correctly and free floating the barrel is one of the first steps.

May 24, 2006, 01:50 PM	#5
tINY Senior Member Join Date: April 26, 2005 Location: Orygun Posts: 2,589	Doesn't that have a wood stock? If it does, a slight wander like that is pretty normal, unless you don't have any weather where you are at..... -tINY