View Full Version : glass bedding question
01-19-2008, 02:10 PM
How much room do you allow in barrel channel for a free floating barrel? I'm going to full length bed this rifle but I want to leave the barrel free floating.
01-19-2008, 04:17 PM
Wood or Fiberglass stock, already finished or not?
01-19-2008, 04:57 PM
It is a wood stock, and yes it is already finished. Also does barrel length have anything to do with amount of space when free floating a barrel ?
01-19-2008, 06:42 PM
The usual standard I applied was a $1, which would slide under and around the barrel for it's full forearm length- it would normally stop at your bedding (depending on the style of bedding performed) or the front of the action/recoil lug, again depending on the mfg. Be sure and reseal the wood, it's guaranteed to move otherwise. When in doubt, use the $1 bill test. A set of barrel channel scrapers/inletting tools will go a long way here... Good Luck!
01-19-2008, 07:01 PM
I don't think a dollar bill is thick enough myself. I like at a minimum .010" myself and will go more depending on the stock wood. I have seen wood stocks that folks left a dollar bill worth of room swell and cause POI changes quite often.
Depending on the weight of the barrel and which receiver is used. I will bed out to the balance point on some heavy barreled rifles if the barrel tenon is short like on the Mausers.
01-22-2008, 10:21 PM
Along these same lines, I have an older but very nice Remington 722 in .222 that I think could shoot much better if the barrel were floated and the action glassed. But it has this "Knot" part way down the barrel that has a dove-tail for the open rear sight.
How do you relieve around that without it looking terrible?
I hate to mess up such a nice original rifle.
01-23-2008, 10:12 AM
A lot of how you determine clearance on a free floated barrel depends on how the rifle is used.
If it is always shot from bags or some sort of rest put it on that rest as it would be used and use the dollar bill to check it, I have seen cases of the barrel being floated when the rifle was standing on it's butt but when laid on the bags it would warp into the barrel.
Another case is if the rifle is used with a sling. Make sure that when the sling tension is adjusted the forend isn't warped into the barrel. It is usually an uglier float job because of the extra side clearance needed.
On the 722 simply give the swell for the sight the same clearance as the barrel. Cut a narrow strip of paper (1/4") and use it to check around the swell as the dollar bill will be too wide and stiff to go around the swell.
01-23-2008, 12:09 PM
About the dollar bill. I went to gunsmithing school and was taught the dollar bill thing there, I've heard it all my life. In gunsmithing school they teach you how to fix guns, NOT how to make them shoot. Now that I've learned something about accuracy I have absolutely no use for the dollar bill trick, it's actually WORSE than useless! Using such close tolerance certainly will not maintain clearance through the recoil cycle, instead the barrel will randomly bounce off of the forend material every shot.
IMO, if you want the rifle to look good, if you want close wood-to-metal fit, then do the dollar bill thing but add a pressure point at the forend. The easiest way I know to do this is to drop a glob of epoxy or silicone/rubber into the barrel channel and hang a weight from it.......a weight which corresponds to the amount of pressure you'd like to achieve. Elmer Keith and Jack O Connor actually agreed on this one ;) probably their only known area of agreement re rifles....downside of this method? When shooting slung any pressure will affect your point of impact.
The answer from an ACCURACY standpoint is very simple..............get enough clearance that you can't make the forend hit the barrel even with a smart rap from the heel of your hand. And I do mean a smart rap. Hold the rifle by the pistol grip, pointing up, and SMACK it with your open palm. Smack it straight up and down and also check for sideflex........sling up and see if you can flex the forend to touch or have an assistant slap the side after you're pressured up. (NOT your loverly wife! :D ) If you can get it to touch easily then it'll touch when you fire it. Clearance needed will be dependent upon material and bedding but I can't see less than 1/8" being enough.
That's how I see it, "form follows function" in my world.
01-23-2008, 01:11 PM
I agree--the dollar bill test just doesn't get it for wood stocks.
If you want close wood to metal fit, don't free float. If you do free float, hog out more wood than you think necessary.
The old Model 70s have the barrel boss (like the Remington 721-722). I have several that were free floated. It is hard to inlet around the boss, especially at the radius, but you have to learn to live with the appearance. All things considered it's not that bad.
01-23-2008, 01:57 PM
alinwa is absolutely correct, most people worry more about beauty than function.
Floating a barrel as I previously instructed gives the customer two things he wants, a free floated barrel and a thing of beauty. You can show him by using the dollar demonstration and he is happy.
The thing that he does not know is that he will in some way negate this form of floating by his own actions using a sling or improper storage (moisture), or some other means.
But he is happy and I don't have to hear him complain loudly to all who will listen that I "ruined" his stock.
Like many things involving firearms, many people want things done to their firearms that they have "heard" about but put so many retraints, such as looks, on how the job is done that the end work looks like what they want but in reality does not function like it should. i.e. close fitting floated barrels.
01-23-2008, 09:33 PM
...the few times I tried simulating some upward pressure on a free floating rifle by shimming, accuracy went to pot. How do you know where and how much to add on a given rifle?
I have a Rem 40X .22 with adjustable pressure screws that I'm afraid to mess with because it shoots so well as it is.
Looks like a real "crap shoot" to me.
01-23-2008, 10:45 PM
I used to have a factory Husqvarna .246 Crown grade back when they made them on the small ring Mauser action with upward barrel tension. That rifle would shoot cloverleafs day in day out with Hornady 75s or 87s & a good load of Norma 204, up until the week I took it into the high country where the mist was so dense that you drove with your wipers on all the time. When I noticed the butt had grown a sixteenth of an inch all the way round the plastic buttplate, I figured out why my elevation was continually out.
I was also brought up on the sheet of paper clearance & stuck with it until I had a barrel fitted that was finished with a very fine thread pitch to double the surface area & enhance cooling. Not long after I noticed that the front of the barrel channel was marred with a series of fine parallel lines from where the barrel was striking the channel. These days, If I can squeeze the forend up to the barrel, the channel isn't deep enough for me.
01-23-2008, 11:55 PM
Not knowing what your barrel channel is inletted for and what contour barrel you now have it's hard to make an accurate statement concerning the clearance you need or have now. Before I started doing my own barrel work I had always performed my own stock work. As a general rule of thumb, I try to have the ejection port of the receiver running level and true with the ejection port of the stock, I donít want the barreled action running up after the job is complete. I apply masking tape, about 6 wraps to start, around the barrel where it will be at the end of but still inside of the stock's forearm and just in front of the receiver about two or three inches. The 6 wraps of masking tape will give you approx. .030" spacing in the channel. I adjust the tape until the dry fit is to my liking. If you are bedding a rifle that has a shallow forearm and a larger barrel, this method may not work until you enlarge the barrel channel slightly. When I bedded my 6BR it was bedded it into an MBR stock and it has a 1.250" straight barrel on it, the barrel channel was inletted for a 1.350" barrel. I used a dial indicator mounted on a mill and indicated the top of the forearm and the top of the barrel as close to .0000" as I could get it. I also checked the dry fit at the ejection ports as I mentioned earlier. When the ejection ports were lined up straight and the barrel and stock were indicated as close as I could get it I called it good. The spacing between the barrel and stock ended up being about .050", equal to about five business cards or, 10 wraps of masking tape :). I just re-barreled a Rem.700 and went from a Remington Varmint taper in a McMillan A2 stock to a LV taper. I had to open the barrel channel up quite a bit for it to work. It's easier than it sounds and masking tape is your friend. Sorry for being so long winded, hope this helps.
01-24-2008, 12:32 AM
After opening up the barrel channel I use two layers of duct tape on the barrel then coat the tape with Johnson past wax and bed the thing. using a slightly taller front pillar can also help get the barrel up, but it should be done when the action is bedded and should only be a hair or two taller.
01-24-2008, 12:42 AM
This might be a nonexistent concern but I like bigger gaps for better air flow around the underneath side of the barrel if the rifle is shot enough to heat the barrel very much.
This might not make any difference but I'm more confident with larger gaps.
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