I've been having some problems with a 300 win mag extracting cases since I got the new barrel put on. The area about .030-.050 ahead of the belt is swelling after each firing with new/and old brass. I've tried rws, norma, and win brass and it all does it. After a round is fired the bolt sticks at the top of extraction. I can take a case that was just fired and it will not go back in the chamber, it stops on the swelled area ahead of the belt. After inspection with a borescope, the smith put a chamfer (v shaped) on the relief cut for the belt and seems that this area is unsupported by the chamber and is swelling. Is the relief cut supposed to be straight or can it be chamferred? My cases are not showing any normal signs of overpressure, primers are still round and no extracter marks, but the belt still swells every time in that area and has to be pushed back by a larry willis collet die before it will chamber.
Gunsmithing Win mag chamber question
- Thread starter jsthntn247
- Start date
Sounds weird man. I have a win mag but they do not stick like you said. Esp with new brass. I am running a Larry Willis collet die too. I'm sure someone on here will help.
Have not tried factory rounds. During load development I loaded from 74 to 78.5 grains of h-1000 and 208 amax's. Anything above 75 bulged the belt and gave me clicks. With my coal, bore diameter, internal case capacity (Norma brass currently) ...etc. quickloads says 76 grains is 50, 436 psi. That's no where near a hot load and the brass shows it, there is no pressure signs on the brass until 78.3 grains and its just a faint ejector swipe.
If its bulging infront of the belt like its unsupported I would like something is wrong with the chamber. Belted magnums headspace off the belt for the first firing, so anything infront of the belt should be supported. Just my thoughts.
Kc
Kc
Where the belt sits in the chamber should be a step down (larger diameter) from the body of chamber. It should be straight just like the rest of the chamber. If he cut a relief cut then your brass is flowing into the relief cut upon firing and causing sticky extraction. Brass swells and then springs back upon firing. The hotter the load the more it deforms (for lack of better terminology) and the less it springs back. Sounds like you need to have someone else look at it and fix it. I wouldn't take work back to someone like that.
The chamfer cut he is referring to in behind the belt, just enough of a chamfer to facilitate feeding without scratching brass. I do all my chambers that way, even though I did not cut his chamber. I know a little bit about this situation. I can tell him without question the chamfer will not cause brass to stick. If I recall when we tried shooting the gun with some of my brass it worked perfectly. I know he has had some bolt issues after he had the bolt tigged on. I think he did a little filing on the action to get the newly tigged on bolt to close.
My guesses, which about all I can do without the action in hand sans the barrel. Bad brass, I know that was an issue once or maybe the bolt can now over rotate enough to engage the opposite abutment. I suspect someone has been trying to pass the buck and giving him some not so good info. Brad taking it back to Don or bring it to me and let one of us pull the barrel and se what is going on and what it is going to take to fix it. Hell you need to come visit anyway if your wanting to work a trade on this 280AI I have.
My guesses, which about all I can do without the action in hand sans the barrel. Bad brass, I know that was an issue once or maybe the bolt can now over rotate enough to engage the opposite abutment. I suspect someone has been trying to pass the buck and giving him some not so good info. Brad taking it back to Don or bring it to me and let one of us pull the barrel and se what is going on and what it is going to take to fix it. Hell you need to come visit anyway if your wanting to work a trade on this 280AI I have.
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