challenges with a barrel bedding block, long barrelled rifle

[wildcat westerner]

We are testing a long barreled magnum rifle for velocities so far, with 8 different powders. Using two different chronographs we have obtained 3,355 fps with a 200 grain bullet. There is an absolute lack of any pressure signs so far. Bolt lift is easy, extraction is consistent, there is no real sign of any pressure in the appearance of the primer, and I know about absolutely "flat" primers! We have been checking very closely for case expansion ahead of the belt and noted nothing or .0005 at max loads, we have reloaded, so far. I hope this is reaching someone with some extensive experience in this area. According to the various reloading manuals I have we are at the max listed loads with absolutely no pressure signs what so ever! Since the rifle is heavy I am shooting it in shirt sleeves, and the weight and Harrel prone muzzle brake, make the shooting enjoyable.
I seem to remember that reloading safe pressures stop at .001 at the portion of the case ahead of the belt. I have overdone this testing in the past and simply do not want to get to primers getting blown out of the pockets with a magnum case, as opposed to a 6 BR.
Also, while the velocities are superior, the accuracy is not exceptional. This is the first rifle I have owned with a two piece barrel bedding block. In order to gain more accuracy from such a unique rifle, what torque do you place on those screws? The barrel is 1 1/2" full bull barrel.
Thank you in advance for your interest in this challenge.

WW

 

[sable tireur]

In general, when discussing barrel blocks, information should follow:

How long is the barrel?

How long is the barrel block?

What material is the barrel block made from?

How many bolts are used to secure the top of the block to the bottom of the block?

What is the thread size of these bolts?

Do you use a thread adapter for material such as aluminum?

Does the block contact the front of the receiver?

Is the block bedded into the stock?

Does the action really free float?

There are more questions I know but this is enough to get started.

 

[Carlos88]

Two piece bedding block? If that's the case and truly two pieces, the chance of them being aligned is as likely as me flying to the moon.

It needs to be bedded with Marine Tex or Devcon (stress free, as in not tightened down). It only takes 15-20 in/lbs to stress an an action. Then tighten to 50 in/lbs with red loctite if using socket/allen head screws. Slotted use blue. Another is Vibra-tite.

 

[338 dude]

We are testing a long barreled magnum rifle for velocities so far, with 8 different powders. Using two different chronographs we have obtained 3,355 fps with a 200 grain bullet. There is an absolute lack of any pressure signs so far. Bolt lift is easy, extraction is consistent, there is no real sign of any pressure in the appearance of the primer, and I know about absolutely "flat" primers! We have been checking very closely for case expansion ahead of the belt and noted nothing or .0005 at max loads, we have reloaded, so far. I hope this is reaching someone with some extensive experience in this area. According to the various reloading manuals I have we are at the max listed loads with absolutely no pressure signs what so ever! Since the rifle is heavy I am shooting it in shirt sleeves, and the weight and Harrel prone muzzle brake, make the shooting enjoyable.
I seem to remember that reloading safe pressures stop at .001 at the portion of the case ahead of the belt. I have overdone this testing in the past and simply do not want to get to primers getting blown out of the pockets with a magnum case, as opposed to a 6 BR.
Also, while the velocities are superior, the accuracy is not exceptional. This is the first rifle I have owned with a two piece barrel bedding block. In order to gain more accuracy from such a unique rifle, what torque do you place on those screws? The barrel is 1 1/2" full bull barrel.
Thank you in advance for your interest in this challenge.

WW

 

[tobnpr]

Also, while the velocities are superior, the accuracy is not exceptional.

I can count on one hand the number of times max load (not necessarily book, but flattening or cratered primers) resulted in best accuracy. Whatever you're shooting is obviously seriously overbore to begin with. Yeah, barrels are like tires- but do you really want to burn out the leade in a few hundred rounds by burning as much powder as you can? I'll trade a little less velocity for a couple more clicks and better accuracy every time.

 

[wildcat westerner]

Hello to everyone who has replied to this site.
Your trying to help me, so I shall try and supply you with more precise information. The barrel was built by Pence and fluted by Otto. It is a full 33 inches long and full length 1 1/2" in diameter. The barrel bedding block was created by my gunsmith and is thick walled industrial aluminum tubing and has a 1/2" thick 2 inches wide, aluminum block recoil lug heliarced? to it. The gunsmith relieved the areas where the 14 screws were drilled and tapped. After all this work was done, then it was the block was then cut in half lengthwise so the barrelled action could be fit into the block. The block was epoxied into an extremely stiff prone stock I had with nearly a full length bedding block already in it. The gunsmith relieved the barrel at bedding block site 1/4" so it would fit inside the bedding block. Even with the 1/4" relief all around the barrel at this site it is still a full inch thick at the barrel bedding site.
We used the existing stock action bedding to set the block into the stock., but the action is free floated above this bedding. The action is a Kelbly tactical, with a magazine. I have never attempted to use the magazine yet.
There is a muzzlebrake with vent holes only in the top half of the brake. I have shot regularly designed radial muzzle brakes from the prone and the ruckus raised by the gas action was Desert storm II!
All bullets fired so far have been meant for the old 33 Winchester lever action cartridge. Fine for velocity testing, but never meant to be shot at such high velocity. 100 fps velocity jumps in a big 338 caliber cartridge seems to really get attention on this site. MY next testing will be carefully done, as to watching for pressures. Then I will take the powder (s) tested and start working with REAL serious bullets meant for hunting purposes.
My background is target shooting at 1,000 yards. I know about precise reloading components etc. We have carefully chosen 50 of the most uniform 700 cases for this rifle. My choice for the .338 Win mag was because when you look at all the cases larger than this, and there are several, the win mag sems almost efficient in size, when you compare these cartridges' velocity for the powder used in these cases. I don't demean the Edge, Lapua or 338-378, I simply chose the win mag with this long barrel and it already exceed with the max listed 338 Lapua 200 grain reloads, with no pressure to this point. The accuracy is laughable, but to this early point I have yet to fire a serious ( Hammer, Barnes or BadLands precision) bullet down this barrel. I am assuming 2,000 rounds from this cartridge due to its bore diameter and the fact of the high velocity, so far comes from loads a lot smaller in size than from the much more larger cartridge cases.
So these are the choices I have made for this rifle. Some rifles in this caliber have really pushed me around on the bench. (338 lapua Improved and a 338-378 Weatherby). So far this rifle has been easy to shoot.

Thank you for your interest.