View Full Version : Glass Bedding

12-18-2008, 08:02 PM
I've been convinced that bedding is a positive step towards accurizing a rifle. I performed this on my .204 and the job looks really good. I have also been led to believe that the smaller the barrel the more support it likes. This gun has the usual support at the end of the stock so I didn't mess with it at this time. I loaded five shot groups and found that my gun liked nothing. When I dissasembled the gun to look it over I noticed that the barrel did not sit in the bottom of the stock, but rather at the four to five o'clock position. I feel that this was a problem because the barrel was held only by one spot instead of held solidly around the barrel. I filed this area out and glassed this area, perfect right?

Well here is my question, the barrel is now in perfect alignment, but has no pressure holding the barrel in any one direction. You can unseat the barrel very easily by hand where prior it required quite a bit of pressure to do this. Should I have maybe placed a shim below the action to do the barrel bedding job, then when removed there would be say .002 or so pressure along with the barrel being supported half way around to create a more stable barrel? Thanks Larry

12-18-2008, 09:01 PM
I don't know that I can answer your question specifically, but you might find what you're looking for after thinking this over.

Usually I bed an action in an older stock so that it doesn't move around under recoil when I float the barrel - i.e. I don't want any part of a wood stock touching the barrel, but I want the action mated to the stock as solidly as possible. Pressure points affect barrel harmonics and can have a marked positive or negative effect on any given load. Some gun makers always use stocks that put some pressure on the barrel, but in my way experience, it often just increases the POI shift when the stock moves. That said, some barreled actions shoot their best groups with a certain amount of upward pressure, which is why it is still done. Harmonics can also be adjusted with dampeners or screw on weights (like the BOSS System) that alter the barrel's length to tune it to a particular load.

BUT, if the stock is wood, no matter how well it might be sealed, full length bedding of the barrel can cause it to move with every change in humidity that effects the stock, leaving you with a rifle whose POI can change unpredictably from day to day. It makes much more sense to do it (if you must) with a synthetic stock, and on a hunting rifle, it might be a good way to keep moisture and debris out of the barrel channel. This is not to say that doing so would have a positive effect on group size or that it is a good idea to bed anything more than the action itself. My most accurate bolt action rifles all have free floated barrels, regardless of barrel profile or length, and most that shoot lighter recoiling rounds I have not bothered to bed the actions, either.

In other words, I consider action bedding to deal with specific issues, not as a prophylactic approach that brings great improvements every time. It can help a lot under the right circumstances, and the more recoil the round produces, the more it makes sense to have the best possible contact between action and stock. I have yet to see a case where bedding the entire barrel helped accuracy, but I'm not saying it can't happen. Some people like to bed the first couple inches of barrel, some like to go even farther. Experimenting is always a good thing, even (or especially) when it teaches you what NOT to do next time. The bottom line is always: did it help? Sometimes we try new things and they work great, even if the why escapes us or what we did appears to fly in the face of logic. I have certain tools I can only swear at in Russian to get them working properly, English only makes matters worse. Whatever works.

More than once I have observed that a mere 5lb of upward pressure to an otherwise floated barrel made a big difference. To see if it will help a rifle, I put a 1" wide piece of rubber innertube between barrel and stock and move it back and forth, tightening the stock screws, and shooting groups when it is in different positions. When it works, it makes an instantly noticable difference, then a pressure point can easily be formed with epoxy at that point (not always way out at the tip of the forend either).

Still and all, with a wood stock, the farther I can keep it away from the barrel the happier I am.

12-19-2008, 09:17 AM
Good morning The above +1 . I use buiness card stock as my test shims cut 1/4 inch wide and the width of the card (not the length) .. I had not thought about inner tube so cannot say if that is a better method.
THE MOST ACCURATE 30-06 I have ever owned (still have) came from the factory Bedded in a walnut stock with a slight blob of material in the barrel channel about 1 inch long at the end of the walnut stock. Bought it in 1979 (CZ) I have fired it about 2000 rounds and last time I fired it (it is in Illinois) it still holds under 1 " at 100 yards with any J thang over 130 grains with my proven loads. Cast It really liks the 180 gc flat nose RCBS at around 1850 - 2250 fps ... I never tried another boolit as that one does so well I have not bothered with another.

12-20-2008, 04:42 AM
Thank you for the reply's. I guess what started this was I heard that floating your barrel was a good thing, so I did just that to my 7mm a couple years back. Well it proved to be just the opposite on this gun, I can't say that it was a real fair test because at this time I was not yet reloading. None the less, puting the support back under the barrel tightened this gun back up. I did it the same way I explained on my .204, but I think the larger barrel diameter kept me from noticing how much pressure it takes to unseat the barrel by hand. When I can easily deflect the .204 barrel, it made me think I messed up, yet again. I'm reloading some test loads now and I will try it the way it stands, then start preloading the barrel like you say. Thanks again. Larry

12-20-2008, 05:13 PM
There is no knowing exactly what is going to work best with an individual rifle without trying it. Let us know what happens. I'm never too old to be surprised by anything that works, or doesn't work for that matter. I probably learn more from my mistakes, though I try not to repeat them.

12-23-2008, 02:36 AM
don't forget that after unseating and re seating a bbl it can take up to 20 shots to settle into the bedding and settle down.

01-06-2009, 03:06 AM
don't forget that after unseating and re seating a bbl it can take up to 20 shots to settle into the bedding and settle down.

So if the bedding creates a positive, it might not be present immediately? Do you glass bed the rifle, spend the day plinking, then go to the range to taylor your loads? Or is there a process of tightening the screws in sequence to properly secure the barrel?

Secondly, I finished bedding my .30-.378, the gun disassembles really difficult as it probably should. I was wondering if there was a trick for taking them apart? I used one layer of scotch tape on the front side of the block to give it very slight clearance during the bedding, but it is still quite difficult to get it apart. If I get the clearance perfect to where the gun presses apart and together hard, is that then defeating the purpose altogether. I'm afraid of shocking the scope when hitting it with my hand, but don't want to take the scope off every time I disassemble the gun. Thanks guys

01-06-2009, 03:47 AM
the point of bedding is to tighten everything together.
and to reduce flex in the stock, as much or more than anything.
i have always had to break the seal by hitting the bottom of the bbl.
once you have everything "set" yes including your magazine well.
and have it put together there is no reason to take it apart again.
except...... to adjust a trigger or to bed the bbl into the action.
i always try the bbl floated first unless i have decided through the card trick that the bbl likes a pressure pad at the tip.
experiment with the cards make a decision then do it, then shoot it a bit for groups, then go. for the reloading accuracy a bit further.
this should fine tune your rifle about as far as it can go.
don't forget to let your glass dry for a good week.

01-10-2009, 02:59 PM
like says versifier your barrel can shoot better with a weight add
try the barrel deresonator made by limb saver
you don't alter the rifle it cost few , i have good success in a 77 tang safety
in 257 rob
regards good luck