quote:

Originally posted by Busheler:
Heat is a bane,in something wearing shy of proper stress relief. Agg's settle,once things foul a bit.

What tube? Base/rings/glass?

quote:

Originally posted by Busheler:
You are in well over your head,on all counts.

quote:

Originally posted by butchloc:
at a guess its either that the barrel is hitting the forend as it warms up and warps a bit or you have a bad barrel

quote:

Originally posted by frank4570:
I have a Savage action. I removed the 7mm barrel and replaced it with a pre-chambered .458 win mag barrel I bought from midway. Accra glassed it, and went to load development.

After some truly terrible groups, I took my best load and waited 5 to 10 minutes for the barrel to cool between shots. Groups went down to .75 inches. It was pretty hot when I was doing this.

Is this to be expected? Anything I can do about it?

This is my first rifle project, I have been under the supervision of a local gunsmith.

quote:

Originally posted by Westpac:

quote:

Originally posted by frank4570:
I have a Savage action. I removed the 7mm barrel and replaced it with a pre-chambered .458 win mag barrel I bought from midway. Accra glassed it, and went to load development.

After some truly terrible groups, I took my best load and waited 5 to 10 minutes for the barrel to cool between shots. Groups went down to .75 inches. It was pretty hot when I was doing this.

Is this to be expected? Anything I can do about it?

This is my first rifle project, I have been under the supervision of a local gunsmith.

Yes heat can do it.

If you cut a rifle barrel into 6 inch sections and measure the wall thickness in all the sections, you will discover that the wall thickness varies from one end of the barrel to the other.

If you kept track of what location the wall was at it's thinnest point, you could somewhat predict which way your groups would move as the barrel got hot. Of course if the barrel is floating you can accomplish the same thing by watching which way it moves as it heats up.

This is one reason a lot of rifle perform their best when their barrels are free floating. It gives the barrel some room to move without compounding the problem further by making contact with the forearm.

Making sure your barrel isn't colliding with the forend as things heat up would be my first suggestion.

quote:

Originally posted by majestrate98:
This just further reinforces the fact that a top quality barrel will always perform.

quote:

Originally posted by Westpac:
A top quality barrel is only as good as the installation. A poor barrel expertly installed is still a poor barrel. A great barrel poorly installed is a hanging offense.

quote:

Originally posted by majestrate98:
If you bought the barrel from MidwayUSA, you have my sincere regrets. Most likely it is an Adams and Bennett barrel. If you do some research, you will not find too many complimentary statements about those barrels from anybody interested in accuracy. Don't read only the reviews on Midway, they're biased. Try other sites, like this forum. Unfortunately, I did my research after I got the barrel.

With the A&B barrel, my best accuracy was 0.75" but that was only twice out of over 100 groups (500+ rounds). Most groups were over 1.5"! I finally had the barrel replaced with a Shilen and group sizes shrunk to a range from 0.60" to 0.90" - all the time, not just once in a while - with every bullet fed through it. All my groups are five shot groups, so barrel heat does become a major factor. This just further reinforces the fact that a top quality barrel will always perform. Overall, I spent twice the money on gunsmithing not to mention the time and ammo wasted.

As they say, the sweet taste of a low price is quickly replaced with the bitter taste of poor quality.

quote:

Originally posted by frank4570:
Thanks a lot for the input. I'll do as you suggested and read reviews on the barrel.

There were 2 major points behind me building this rifle. One was to start learning how to do this stuff, I have actually do it and make some mistakes in order to learn. I don't know anybody who was born knowing how to be a gunsmith, luckily I have a gunsmith for guidance.

The other point was to see if I liked the .458 win mag as a cartridge. And I have to say, for my style of hunting, I just love it. If I find that this barrel just won't shoot, I'll probably buy a good barrel.
Unfortunately, nobody around her shoots anything like this, so I'm kind of on my own with this big cartridge.

quote:

Originally posted by majestrate98:
If you bought the barrel from MidwayUSA, you have my sincere regrets. Most likely it is an Adams and Bennett barrel. If you do some research, you will not find too many complimentary statements about those barrels from anybody interested in accuracy. Don't read only the reviews on Midway, they're biased. Try other sites, like this forum. Unfortunately, I did my research after I got the barrel.

With the A&B barrel, my best accuracy was 0.75" but that was only twice out of over 100 groups (500+ rounds). Most groups were over 1.5"! I finally had the barrel replaced with a Shilen and group sizes shrunk to a range from 0.60" to 0.90" - all the time, not just once in a while - with every bullet fed through it. All my groups are five shot groups, so barrel heat does become a major factor. This just further reinforces the fact that a top quality barrel will always perform. Overall, I spent twice the money on gunsmithing not to mention the time and ammo wasted.

As they say, the sweet taste of a low price is quickly replaced with the bitter taste of poor quality.