should i bed the barrel.

[ajhardle]

I have a 32" 300 rum barrel that weighs almost 8 pounds laying around for a future build. Truing the action should releive stress from compressing two uneven surfaces, correct? By adding a ridiculously long and heavy barrel with only 1.25" bearing surface, would seem to add a lot of stress. Do you think I would be better of by bedding a portion of the stock under the barrel?

 

[Joel Russo]

Yes. A barrel that long and heavy needs some support! I would suggest a few inches in front of the recoil lug...

I just bedded this one, and yours should look similiar.

 

[ajhardle]

Mine should look similar. Yes, but probably not quite that pretty. It looks like you do some nice work.

 

[ajhardle]

Also, I assume it takes a very rigid stock to be worthwhile?

 

[Joel Russo]

The better the stock, the better the results. Even the "tupperware" stocks will benefit from a good bedding job.
Thanks for the compliment. I've put some sauce to a few stocks.

 

[Bart B]

I wouldn't if accuracy and keeping zeros on sights are important.

Folks shooting barrels of any weight or length in competition winning matches and setting records never bed under barrels; they know better. It causes different amounts of shot stringing (mostly vertical) because the stock's fore end bends in all directions depending on the pressure on it from how the rifle's held. And some stocks' fore ends bend a bit with temperature and humidity changes.

Just bed the receiver; that's all that's needed. Keep at least 1/16th inch clearance around the barrel; more at the front end if the fore end's a flimsy one. If the support for a long heavy barrel from just being screwed into a receiver and nothing touching the barrel wasn't enough, totally free-floated barrels wouldn't shoot as well and consistant as they do.

It's a myth that such barrels need support under them.

Regarding rigid stocks, I don't think it matters very much. Stocks are like barrels, they all bend and wiggle when the rifle's fired. As long as they're repeatable doing so, all's well in the accuracy department.

 

[FEENIX]

+1 on what Joel Russo's response. Yes, he does beautiful work and knows what he's talking about, you should see his masterpieces in his website (Home Page).

BTW, you should see his bad *** groups on some ridiculous bad *** long distances ... he's too humble to say anything but he's an accomplished and refined LR shooter/hunter.

Here's one ...

Sorry Joel, I hope you don't mind.

Cheers!

Ed

 

[Joel Russo]

Thanks for the kind words FEENIX, I've been fortunate to have shot some good groups at extended ranges.

The topic at hand, can be a controversial issue indeed. A short range benchrest rifle, with a custom action that has a longer than normal tennon, typically will not benefit from chamber bedding. The original poster is shooting a .300 RUM with a long heavy barrel. I may be wrong to assume, but I'll assume, that he is not intrested in shooting short range benchrest competition. I'm pretty sure he is building hunting rifle capable of taking game at reasonable distances. My experience is that these types of builds will benefit for a chamber bed.
This brings me to the bedding block discussion.... Bedding blocks generally enable a rifle to be more consistent, but not necessarily more accurate. This is the same concept for a chamber bedded barrel. The bedding supports the barrel, and deters movement at the critical barrel receiver junction.

Try holding a 32" long, 8lb barrel by 1" at the end, and see how long you can hold it in the horizontal position...

The stock in the picture that I posted, was from a .338 Lapua build, with a long heavy barrel.

I never shot short range benchrest competitions with small calibers, but I have shot long range and extended range competitions with large calibers. My experience in this discipline is that these builds benefit from chamber bedding.

Hey, just my .02...

 

[Bart B]

A short range benchrest rifle, with a custom action that has a longer than normal tennon, typically will not benefit from chamber bedding. The original poster is shooting a .300 RUM with a long heavy barrel. I may be wrong to assume, but I'll assume, that he is not intrested in shooting short range benchrest competition. I'm pretty sure he is building hunting rifle capable of taking game at reasonable distances. My experience is that these types of builds will benefit for a chamber bed.

Typical short range benchrest barrels are much shorter and therefore stiffer than 26 to 30 inch ones used in NRA high power long range competition. Their resonant frequency's higher and they whip very little with the 22 and 24 caliber cartridges they shoot. Those longer barrels in larger calibers have a lower resonant frequency and they whip a lot more with larger cartridges burning a lot more powder. Which is why it's more important to not have anything under the chamber part of the barrel except air. Even in short tenon barrels in Win. 70 box magazined receivers totally free floated shoot as accurate as long single-shot actions with long barrel tenon threads. It ain't about stiffness; it's about repeatability. . .for accuracy, that is.

Bedding blocks generally enable a rifle to be more consistent, but not necessarily more accurate.

What's the difference between consistant and accurate?

This is the same concept for a chamber bedded barrel. The bedding supports the barrel, and deters movement at the critical barrel receiver junction.

If you don't think a barrel without bedding under its chamber moves at its junction with the receiver, such barrels are not torqued in tight enough.

Try holding a 32" long, 8lb barrel by 1" at the end, and see how long you can hold it in the horizontal position...

This proves that humans typically can't do it. But it's not important 'cause we don't hold barrels that way when they're shot.

. . . .I have shot long range and extended range competitions with large calibers. My experience in this discipline is that these builds benefit from chamber bedding.

A popular belief with long range NRA high power lower classified competitors. 'Tain't so with those in high master classified shooters winning matches and setting records.

 

[Joel Russo]

I started my last post by saying that this is a controversial topic, and I have tried to provide the initial poster with some information that I have personally experienced.

I have developed a way to chamber bed these particular rifles that will place the barrel in a neutral or improved state, never a negative state.

Your mileage may vary, and you can disagree, but I have proven my methods.

I know what works for me, and have the targets to show it.

I'm finished with the debate.

 

[ajhardle]

To make things more controversial, my barrel is threaded for a savage. I imagine I can still make it work as long as the contour is straight at that portion.

 

[Bart B]

I have a 32" 300 rum barrel that weighs almost 8 pounds laying around for a future build. Truing the action should releive stress from compressing two uneven surfaces, correct? By adding a ridiculously long and heavy barrel with only 1.25" bearing surface, would seem to add a lot of stress. Do you think I would be better of by bedding a portion of the stock under the barrel?

Yes, truing up the receiver face square with the barrel tenon threads in it will true the action enough. Be sure the receiver's face will be square with the barrel tenon threads, not the boltway axis; that boltway's not always aligned with the barrel tenon threads.

There's not enough stress from an 8-pound long barrel hanging off that receiver to get concerned about. When that .300 RUM barrel whips as its fired, the stress on the receiver where the barrel shoulder fits hard against it will be a lot more than what the weight of the barrel alone puts on it. Its muzzle will whip through a much greater vertical arc either side of zero when fired that what the barrel normally droops below zero at rest from its own weight.

After the receiver's faced off, that's a good time to thread in a collet with a stopped end mill in it whose cutters are at the diameter of the bolt face. Using that setup will get your bolt face square with the barrel tenon axis and your fired case heads will be square. Otherwise, you'll end up with out of square case heads and that's a detriment to good accuracy.

 

[Bart B]

I have developed a way to chamber bed these particular rifles that will place the barrel in a neutral or improved state, never a negative state.

Your mileage may vary, and you can disagree, but I have proven my methods.

I know what works for me, and have the targets to show it.

Post some pictures of 20-shot groups fired in 15 minutes at 800 to 1000 yards that are under 1/2 MOA and I'll believe you.

 

[Bart B]

Bart. . . .but i do not know you, could you tell me how you have the knowlege to say what you say about the subject. . . .maybe your point on the subject is from doing both (bed the barrel and compareing it to no beding under the barrel)

My experiences are from epoxy bedding several barreled actions in both wood and synthetic stocks. Doing that work myself's been enjoyable as I shot high power competition for a few decades winning my share of matches, wearing out 15 to 20 barrels for .308 Win. as well as 26 and 30 caliber magnums. Got classified by the NRA in the top 2% of all long range competitors as well as being selected for and shooting on a few US national and international teams.

With two .308 Win. barreled actions and two more 30 caliber magnum ones, they first were bedded under the chamber for 2 inches. Tested them for accuracy with 20 shot groups at 600 or 800 yards for the .390's and 1000 yards for the magnums. After each group for each, the barreled action was removed and 1/2 inch of under-chamber bedding was removed then reinstalled and stock screws torqued to their values. As the barrels heated up, vertical shot strining happened. For each 1/2 inch of bedding removed, accuracy improved a bit and vertical stringing lessened. When it was all removed and the barrels were totally free floating, they shot most accurate for 20 to 30 shots. I did this long ago 'cause a couple of friends, both Nat'l champions, suggested I not bed under the barrels anywhere after I did on my first match rifle.

Being a bit skeptical because of its popularity, I did it anyway then tested each as mentioned above. Had to admit, they were right. None of them and others of their ilk put bedding underneath their barrel's chamber area. I don't know of any benchresters that do it, either. When I don't bed under that part of the barrel, they shoot as accurate as long range benchrest rifles do. I don't know of any rifle with contact bedding under the barrel's chamber that'll shoot inside 3/4 MOA at 1000 yards for 20 to 30 shots fired in 20 to 25 minutes; that's what has to happen testing rifles (and ammo) used in high power competition in long range matches.