7-300 Win chamber issues

razrbak

Well-Known Member
Joined
May 23, 2012
Messages
51
Hey all,

So I had a 7-300 win built for me by Rbros rifles late last year and love everything about it! I love it so much I wanted to build one for my Dad. I called PTG and talked with Dave and ordered a 7-300 win reamer with no shoulder changes and a long throat for a 180 vld. I got an email with the print, and I'm no pro at reading prints, but everything looked great. First pic is that print
Screenshot 2015-03-09 20.28.13.png

Six days later I got another email from PTG with what I thought was the same print, but it said 7mm pratical. I didn't look it over very well, and now I notice that it has a 30 degree shoulder.
Screenshot 2015-03-09 20.30.57.png


The reamer showed up, I gave it to my gunsmith and he cut the chamber. A 300 win go gauge closes in the chamber just fine, but I couldn't get the brass I had prepared to chamber. On closer inspection, I realized that the reamer does have a 30 degree shoulder angle and a longer neck. Looking at the print, its very similar to the balistic studies 7mm Practical.

SO, my question is this. I feel like the chamber needs to be cut deeper to acomodate a 30 degree shoulder, but if the go gauge fits as it is, it seems obvious that cutting the chamber deeper would create some serious headspace issues. My thought would be to take the brass I prepared for my other 7-300 that chambers just fine, and cut the problem chamber deep enough to chamber my prepared brass. Then would the brass not fire-form to a 30 degree shoulder and I could continue life as normal with my redding type s neck die?? Any comments would be greatly appreciated.
Thanks
 

bigngreen

Well-Known Member
Joined
Nov 24, 2008
Messages
8,336
Location
SW Montana
You've been Kiffed!! The least painful thing to do may be to get a set of dies made for the current chamber, you can not run a reamer in deeper because of the belt.
 

Edd

Well-Known Member
Joined
Jan 26, 2011
Messages
3,814
Location
Tulsa
You have two choices. I think your best one is to get some loading dies for the 30° chamber. A standard full length sizing die should push that shoulder/neck junction back .033" without issues.
 

IdahoCTD

Official LRH Sponsor
Joined
Oct 22, 2008
Messages
1,916
Location
Boise, ID
You can try to use a 7RM die to push the shoulder back enough to fireform some brass that can be sent off for a custom die. Looking at the print it's actually only .002" longer to the body shoulder junction and .001" larger at the shoulder. The neck/shoulder junction is longer on the 7-300wm because of the shallower shoulder angle. A 7-300wm die should push the shoulder back far enough to chamber.
 

razrbak

Well-Known Member
Joined
May 23, 2012
Messages
51
Yes PTG has given me enough problems at this point its not looking good for future business.

Thanks for the replies. I fiddled around with it last night and did eventually get brass to chamber by pushing the shoulder back with a 7 RM full length die. I contacted Redding and Hornady about custom dies off of the reamer print, so we will see what happens. I'm a bit nervous to try and fire form the brass that I pushed the shoulder back using the 7 RM die. The shoulder/body junction is significantly lower than my necked down standard 7-300 brass. Here is a pic with the loaded round, simply a necked down 300 WM, and the other two with the shoulder pushed back.
2015-03-10 09.26.34.jpg

Im a little frustrated, but I would like to make it work with either some custom dies or fire forming. I don't want to buy a new barrel! Would fire forming with pistol powder and cornmeal be a good idea to see what I'm dealing with?
Thanks
 

IdahoCTD

Official LRH Sponsor
Joined
Oct 22, 2008
Messages
1,916
Location
Boise, ID
Is that pushed back enough to just chamber with resistance on the case? If so you can fireform just like that. Otherwise set the 7RM die so the cases just go in the some resistance. If your worried about it jam the bullets in the rifling a bit to help some. Belted cases don't really need contact at the shoulder, because they head space off of the belt, but if they don't have it for fireforming they tend to stretch in front of the belt upon firing. That can lead to premature case separation/failure. Fireformed cases (actually fired cases are the best) are better to order a die from instead of a reamer print. A print is what the reamer is suppose to be not what the chamber/reamer actually is. After you fireform the cases you can reload them with the 7RM dies and fire some normal loads to send cases off. Whidden makes some nice dies as well.
 

razrbak

Well-Known Member
Joined
May 23, 2012
Messages
51
Is that pushed back enough to just chamber with resistance on the case? If so you can fireform just like that. Otherwise set the 7RM die so the cases just go in the some resistance. If your worried about it jam the bullets in the rifling a bit to help some. Belted cases don't really need contact at the shoulder, because they head space off of the belt, but if they don't have it for fireforming they tend to stretch in front of the belt upon firing. That can lead to premature case separation/failure. Fireformed cases (actually fired cases are the best) are better to order a die from instead of a reamer print. A print is what the reamer is suppose to be not what the chamber/reamer actually is. After you fireform the cases you can reload them with the 7RM dies and fire some normal loads to send cases off. Whidden makes some nice dies as well.

That makes sense. The shoulder is pushed back just enough to chamber with some resistance. I emailed Whidden, and Ill see what I can do about fire forming and getting some cases sent to them. Looks like I might be able to make the barrel/chamber work without pulling my hair out Heck, maybe it will outshoot my 7-300 ;)

Thanks for the help guys
 

Recent Posts

Top