fore end pressure guide line?

[nekshot]

I am a fan of free floating barrels, however I have a brandnew M98 military profile 7mm mauser barrel that is a puzzle to get decent groubs. I am going to start putting pressure under barrel at front of stock. Seems to me I once heard pressure should be about 15 pounds. I ask of those that know, what type of material(this is my new personal hunting gun) that will take weather elements and do you put the material on the bottom only of barrel or bring it up the sides a little. I am leaning towards putting a bead of silicon on stock and after it sets up install action. The larger the bead the more pressure on barrel. I realise this could take alot of time but that I have! Thanks for your input. For those that must know it is a vz24 in a glass bedded action only stock and a 19 inch military barrel- brand new.And I am using jacket bullets until I get it to shoot decent then I will go to cast. My standard of 1 MOA is discarded for this barrel and I will be satisfied with 1 1/2 inch moa at 100 yards.

[waksupi]

Start putting layers of paper under the stock tip until you see improvement. Once you find this, put some epoxy or Acragel on the fore end and re-seat the action and barrel using the paper layers as a spacer. Silicon won't be sturdy enough.

[DougGuy]

I free floated my 1970s Ruger M77 .308 barrel by removing the little hump ruger put at the end of the stock, oh boy it did NOT like free floating at all! So.. When I bedded it in Steel Bed, I suspended the muzzle with a cable from overhead, rested the buttstock on a table, and tied a 100rd box of .45 Colt ammo to the front sling swivel, then tightened the action screws, squeezing out and cleaning up bedding as I went. When the bedding set, I removed the box of ammo and had right decent upward pressure all the way from the receiver out the whole length of the barrel that sat in the stock. 20yrs later it still has not changed and the rifle really responded well to upward pressure applied in this manner.

Edit: This is a rifle that will put 3 into a guitar pick @200yds. Bedding the entire barreled action with upward pressure was only part of the tweaks that were done to it, the rest were lapping locking lugs, pillar bedding the action and tang screws, bedding the scope bases, loading fireformed brass and setting .025" freejump to the leade of the rifling when the round is chambered.

[Blackwater]

A buddy of mine has turned dozens of problematic rifles into good to great shooters with forend pressure. He's also gone the opposite way and "free floated" guns that he couldn't put much time in by simply putting shims up under the action, which elevated it enough so that the barrel became free floating. He's an inveterate tinkerer, and has discovered many ways to make guns shoot well. He just simply looks things over, decides what he thinks the most likely cause might be, and addresses it as simply as he can at the time. This has resulted in his using all manner of stuff to put forend pressure on barrels, from glass or silicone bedding, to simple strips of an old floor mat for his truck that he'd cut out and use. The barrel responds to the pressure, and doesn't really care much what you use to achieve it.

One other thing he's noticed is that the thickness of whatever he's used to "accurize" any particular barrel can be important, and if he's really wanting it to shoot, as he often does with his personal guns, he'll try various thicknesses of various things he simply finds around the house that look like they might serve, and tries them. Almost always, one will prove to be the best of the lot, and that's what he goes with for the final effort.

A "finer" way to do it is to go through that, and when you find the right thickness and substance, slide it up just a tad and pour a bead of AcraGlass or whatever you want behind it, and let that cure with the spacer in front, thus, when it dries and solidifies completely, you pull out the spacer and still have the forend pressure from the glass, and that's molded precisely to your barrel.

One other thing: If it's a stepped military barrel, I think I'd likely start just in front of one of the steps, wherever it looks "right" to you. Barring that, just put it where you think best, and do some testing. 3 shots should usually tell the tale, so it's not too expensive to experiment with this. And sometimes, a barrel will really startle you as to the difference it makes. Not always, of course, because nothing works all the time with guns. They're just like us - individuals - and mostly, you just have to keep trying stuff until you find what works with a given gun. Old military barrels may have problems that you can't see, and if nothing seems to work, I'd find a good 'smith who has a bore scope and pay him to look at it. If it's bad, there's sometimes no way to make it shoot no matter how hard we beat our heads against that wall. It's rare, though, but it does happen.n
BTW, he just did this (adding forend pressure) to his grandson's .243, and it went from 4" groups at 100 to a near one holer! It's a Savage on one of their 110 actions, and the boy is elated and as confident now as a young lad can be! I'd hate to be a deer around him now!

[Vann]

I use stainless steel shim stock. I keep .005, .010, and .020 in my shop. It doesn't cost much and won't shrink with age or break down.

[Der Gebirgsjager]

When forend pressure seems called for I use the Accra-Glas method. Assuming a wood stock, I inlet a small rectangular area for the glass to anchor into. Apply a generous (I was going to use the word "liberal" but changed my mind) blob of the stuff into the inletted area and a good coating of release agent (actually I use paste wax) to the barrel, put the action into the stock and tighten the action screws all the way down, then back the front screw off 1 1/2 - 2 turns. Remove the excess glass that has squished out (saves a lot of work later) and let it set up. Then when it's thoroughly dry remove the action from the stock and clean everything up (release agent from metal, excess glass that flowed where you don't want it to be, etc.) then put the action back in the stock and tighten everything up tight. Try it out, and if it seems like there's too much pressure you can sand or file a bit of the pressure pad off until you hit the sweet spot. In the unlikely event that you need more pressure you can repeat the process and build it up. Rifles can be such individuals, and some actually like to be full length glass bedded. 19" barrel? That's interesting.

[nekshot]

it was a 21 inch something brandnew but had some pitting on outside is what gunparts advertised it as. They only got a few and I bought one (should have bought more) and true some storage junk on outside but the first inch or so really was rusted as if they were stored front of barrel on floor and it got wet occasionally. I cut off till bore was free from rust. I pushed a slug thru and it feels like it is true diameter the whole way. I bought some things from them that were seconds for sure but these seem true. I was happy because a new LR mauser military profile 7mm barrel is scarce as hens teeth.

[B R Shooter]

I too am NOT a fan of forend pressure. Any stress or strain on the stock will have an effect on point of impact, such as wrapping a sling around your arm, resting the stock on a hard surface, etc. However, if need be, I would follow waksupi's advice. Add shims, try each time. Stop as soon as you get results. No sense in over doing it.

A friend bought a stock from Stocky's, aluminum bedding block, and his gun wouldn't group. It was a target barreled 308, so not as thin a barrel as a sporter. So I took it home, and there was so much stock pressure, it had the whole action in a bind. After some serious removal of stock, I had it free floated, with plenty of clearance, not the dollar bill thing. It shot quite good for a factory barrel.

[flounderman]

If the barrel needs a decent crown, it won't matter how much pressure you put on it, it still won't shoot. If you cut the barrel back the problem is probably in the crown area.

[BK7saum]

If you knew how much forend pressure you wanted, put the stock in the vice, hang x amount of weight off the forend, put some Acra Glas at the tip, install the barreled action with wax or mold release. When cured you have x amount of upward pressure on the barrel.

[knifemaker]

I have to agree with Flounderman that your problem may be a bad crown after you cut the barrel end. Only takes a very small burr or uneven cut to make groups open up by a large margin.

[country gent]

Check the crown under magnification an make sure its right. I do final crown with a brass ball and fine lapping compound. This removes all burrs and give a uniform edge between barrel and face. will be more important with cast bullets. As to forend pressures try old buisness cards and heavy paper. cut in strips you can add subtract layers until best pressure is found for the barrel stock combination, then coat barrel with release agent ( do the whole barrel as the bedding will flow alot under pressure) move the cards forward and clean roughen stock 3/4"-1" back. Mix and apply coat of bedding agent, acraglass, micro bed, plastic steel, bisonite, jb weld or marine tex also will work here. Dye if you want to match. insert barreled action into stock tightening screws and let cure over night. remove excess epocy once it starts to set up and is still soft. I mask the outsside of the stock and coat this with wax or release agent also. to help with run off over flow. I like to allow to start to set up before removing excess, like alot of things as it sets it may want to draw some more in, If you clean excess befor then there is nothing to pull back in. Barrel tension between stock and barrel is important and finding the right amount is a good way to improve accuracy. Also would recomend driving a slug into muzzle 1" -1"1/2" and back out to see if there is muzzle wear belling there.

[nekshot]

Thanks everyone I have some ideas now how to proceed. I put a target type crown on this barrel and it was perfect back when I did it and used magnifier to look at it. I did spin it in the lathe since a wee bit when I fixed the outside pits so I will have another look at it.I was amazed how much thinner and lighter this 7mm military is over the 8mm military style. Makes for a light weight sporter.

[knifemaker]

There is a easy way to get about 8 pounds of fore end pressure on the barrel. Remove barrel-action. About 1-1/2 inches in from the fore end tip lay a bead of acra-glass from one edge of stock to other side. be sure to put release agent on barrel where it will contact the acra-glass. On the flat area just behind the recoil lug lay a flat shim of about 30-35 thousand thick. place barrel action in stock and tighten the guard screws down. allow to set up for about 48 hours. Remove action and remove shim stock and replace action in stock and tighten down.

This will give about 8 pounds of pressure on the barrel. test fire and see if accuracy improves. If it does, you now know that fore end pressure is needed and may have to try different amounts of pressure for very best accuracy. I have had very good luck at about 8 pounds of pressure for rifles that did not like being free floated. I even ran across one rifle that would not shoot groups under 1-1/2 inches with pressure or free floating. I ended up glass bedding the entire barrel from in front of the lug to the fore end tip and it grouped under 3/4 inches at 100 yards .

[Wolfer]

I too am a fan of free floated barrels if they shoot good like that. With commercial barrels that mic .650 or bigger at the muzzle I can usually free float. Commercial barrels at .550 I will always have to pressure bed.
Exception, 223 barrels at .550 can usually be free floated.

Military barrels, I can't recall ever getting one to shoot good without a pressure point. There's just not enough meat on the back end. Plus they were not designed to be unsupported.

Problem I'm sure most of us here know.
Personally I've never had a pressure point gun that I could just bang off 10 rounds and expect a good group. As the barrel heats up things move around. Usually each shot will be a little higher than the last but I've also seen them act as a heat sink and bow the barrel down on one gun ( rem 760 )

Depending on the heat I can usually get three shots in a group before having to let it cool down.

On a hunting rifle I'm not concerned with general group size. What I want to know is where that first boolit will land in relation to the cross hairs just as the sun breaks the horizon on a frosty morning. This is the one that counts.

My 7x57 wears a commercial barrel 20" long .550 at the muzzle. Free floated it run around 4" at 100 yd. I folded a business card and stuck it in the front and tightened it back down. It immediately went to MOA for 3 shots.
It still has that business card in the stock.

[Frank46]

Your local autozone, pep boys, O'Rielly probably has cork or cork and rubber combination gasket material. Old inner tubes also have been used. Or all rubber gasket material can be used. Frank

[bigdog454]

before you start putting glass or any other permenant materialin you stock try this, remove the bbl from the stock and take a match book and fold it to put pressure under the bbl. go and shoot it and see ir it makes a difference. If not move the match book towards the receiver till you find the sweet spot. I've cured many a rifle with this approach.
BD

[nekshot]

Thanks everyone! I started with cutting up an old nra plastic card and finally the groubs shrank. I am getting 1 inch at 80 yards, not great but a whole better than 3 inches. It is a new barrel and these are the first shots so after a hundred I am gonna try cast. This is my handrubbed stock and it looks great. If I can figure out how to get pics on the forum I'll show it off. Weight is always an issue and this is the first time I got a vz24 in walnut stock with a old redfield wide view 3-9 scope come in right a 7 lbs. This barrel is small compared to 8mm original and feeds like a champ!