What did it look like when you re-threaded it? Did you re-crown also?
Thinking of buying a lathe, how hard is it to chamber a rifle?
- Thread starter WEATHERBY460
- Start date
Help Support Long Range Hunting Forum
Rflshootr
Well-Known Member
Appearance looks good, but it is still deeper than I personally prefer. It's hard to tell from the pic, but it looks like there may be a small burr on the bore edge.
This one was done by Alamo Precision. The bore edge seems smooth to me. Just wanted to show something to compare with the other one. I don't actually know what the ideal crown should look like.
25WSM
Well-Known Member
When I went to gunsmith school over 30 yrs ago we were taught to put a small 45 degree angle at the rifling. A slight chamfer on the edge is more durable than the 90 degree cut. Plus the 90 degree is sharp and can shave the coating off your cleaning rods. The Alamo crown looks like a nice crown to me. Perfect for a hunting rifle. I would still prefer the chamfer on the bore. And if there is a slight burr there I dont see it in my pic and it would be gone after one shot. You should see the burrs on the throat of a fresh chamber job. They look scary but are gone in 5 to 10 shots.
Shep
Shep
Harry Knutz
Well-Known Member
There is nothing wrong with that style of crown, That was what everyone was doing before the 11 degree crown was what everyone was doing, Give it time and there will be a new one and everyone not using the new one will be wrong. Maybe that guy has his own crown called the "Venturi" Crown who knows? It needs to be a very smooth mirror like finish and needs to be perfectly square to the bore.
Any finish as long as it is square to the bore centerline is good.
This brings back fond memories; I have not touch those type of machineries since the late 1980s.
The benchrest crowd of old used the 11 degree crown, who knows they might have started it. When I shot benchrest in the 80s, I never paid attention to the machining aspects of the game.
Fast forward to todays benchrest shooters, almost all the guns I see on the line have straight 90. My brother's group and VFS guns both originally done by Borden have straight 90s. He bought those 10 years ago. Following in the way his barrels were finished, all the barrels I spun up for him since have all straight crowns. The same way I finished VFS barrels for a couple of benchrest shooters at our local club.
My brother's guns are glued, no test fitting there. Have to rely on print and Borden's old barrel for tenon dimensions. The other benchrest guys get 1 day service, can't keep their actions overnight. I am just a hobbyist, not in the business, no FFL. I can do AR barrels no problem.
For my friends I've done a lot of recessed target crowns. Some have straight, and others have chamfer when requested.
I've done over a hundred AR15 barrels, what I learned the straight crown with no chamfer when melonited they tend not to last as we expected. That is losing X count at 600 yards before reaching 5K rounds. We expected for the barrels to last at least 6K. Non-melonited button barrels last 2500-3000 for the top shooters. Meloniting makes the surface real hard that cheap file will just glide on it. With hardness there is a flipside - britlleness. The sharp edge of 90 unchamferred tend to chip off.
A particular melonited barrel with chamfered straight crown lasted 10741 rounds when I pulled the barrel for a buddy. His last 600 yard match was 198-8. The 8 came on the 20th shot.. victim of I-will-clean-this jitters. I pretty much coerced him to give up the barrel so he had a fresh barrel leading up to Camp Perry. His 600 went back to double digits X count.
I better get off the forum, I have 20 AR15 barrels to finish from unturned blanks for the TX JRs. Have to plug in for our sponsor, these are donated barrels by Shilen.. Buy Shilen.
Last edited:
LVLAaron
New Member
Not to hijack the thread... but where can I get the shilen blanks for AR barrels? Do you get them profiled in any way, or do you do that all on your own?
Cheyenne 1
Well-Known Member
- Joined
- Dec 9, 2007
- Messages
- 101
I didn't do it for him. I threaded the barrel off. You can imagine the chamber wasn't any better. I had a 6.5 barrel I had taken off one of my open guns with a few rounds on. I chambered it and gave it to him.
Young guy, not a lot of cash. I hate to see people taken advantage of.
My whole point is that not Everyone takes the time to do the jobs correctly. Mistakes happen, but why send them out that way?
I have worked in trades all my life. And have guys work for me that have many years of experience, yet I wouldn't want them to put air in my wheelbarrow tire. (they didn't work for me very long) It's more about the person and there level of quality.
To a lot of people its quantity over quality.
Last edited:
Do everything from unturned blank. I usually get them pre-turned straight 1.000 to finish 26. This batch of 20 somehow were shipped unturned. Shilen asked to return them for turning, I made the decision not to. These are donation, I just don't want to add any more load to their busy shop.
These are 7.5T SS 4G.
Last edited:
shortgrass
Well-Known Member
I have got turned blanks from Hart. The diameters are correct, the steps are long so you have leeway . I just don't have the time and I could not get paid for turning from a 1'- 1 1/4" straight blank. I agree with the not leaving a sharp edge at the rifling. Was taught 45yrs+ ago that a sharp edge will crack or break before a beveled or radiused edge will. The lesson then was concerning HS tooling, but it carries over into many applications.
Last edited:
