Anyone own a 7mm 300 Win Mag?

[just country]

morning, question? would the 300Norma Mag. brass with the longer
neck be more suitable for the 7-300, or go to a 7-300AI?
r go to a 7-8mm mag? if it wasn't for the lack of bullet weights
for the 8mm mag. this would b a very real thumper.
I really, really like my 340Wee. Just me. GBOT TUM

 

[yobuck]

The 8mm mag case was used, its now known as the 7mm STW.

 

[smack]

I know the last reply to this thread was awhile back. I did a 35 degree shoulder version of the 7mm-300 Win Mag with minimum case taper. I had the reamer done years back and some of the heavier high BC bullets weren't in play back then. My chambering has .188 freebore. I had a Wyatt's extended box installed and went with a 28" Schneider R5 Barrel. I want the rifle throated for the Hornady 180gr ELD-M. I want the bullet/boattail junction just slightly above the the shoulder neck junction when seated. Anyone have any thoughts or expirience on a ballpark for freebore to accomplish this? I'm going to send it to Karl Kampfeld to have the throat extended. I know I can send a few inert cases with a bullet seated where I want it but I don't know if that would handi cap me for other bullets. I guess I'm looking for a happy medium across the board freebore, if that's possible.

 

[Petersen]

I have the same freebore on my reamer/rifle and it shoots the 180 bergers great with rl25. A little More freebore wouldn't hurt though.

 

[smack]

I was just going over some results from the first 24 rounds fired out of the rifle. I was getting pressure signs and some crazy ES's from three shot strings with 77gr of H1000 behind a 162gr ELD-X while fire forming. That shouldn't be happening at that charge and bullet combo (ES-43). I was messing with a fireformed cartridge and tried sliding a 162gr ELD-X into it and it wouldn't even slip into the neck with allot of force. My chamber has a .316 neck. I'm shooting old school W-W Super Brass. A loaded cartridge is .313. That shouldn't be happening. I need to check and see if my PTG reamer is out of spec and not per the print.,

 

[AZShooter]

IMO .003" total neck clearance is too small, this is especially true if you are not turning the necks. Turn all your brass for a minimum of .004" total clearance, even .005" wouldn't hurt. Then you KNOW you have the clearance. Neck tension/bullet release will be more consistent too.

 

[DMP25-06]

Nate I will do my best to give you accurate info here. But first I want to say I am not the origional owner/builder of the rifle. I do not have the reamer but I do have plans to aquire it. And I am working with WW brass that came with this rifle and it is in poor shape. I plan to work up some new brass before I go much further with this rifle. I feel it deserves it. Here goes.

Fired case necks are .3165" loaded cases average .311" + or - .0005"

Shoulder angle looks to be the standard 300 win. I can see no other changes that were made to the case.

I started to have a bit of chambering issues (bit hard to close the bolt) and I was full sizing. So I looked into the length of the neck and found them to be extrememly long. Some as long as 2.656". So I trimmed them to a more standard 300 win length of 2.625" and the problem went away. This was the cases that shot into the same hole at 100 yds and into a 6" group at 1172 yrds.

The rifle came with two sets of dies. A custom set of RCBS marked 7mm-300win. And a set marked the same of Lee collet dies. I did not like the Lee's because they left 4 ridges on the necks and after I fired them some cracked. So I switched to the RCBS dies. I have bushing ordered and will switch to my redding 300 win bushing dies soon.

Seating depth.
The rifle has a long throat. I would assume they wanted a bit of free bore. "O" give with a 180 Berger on the lands is 3.060" I have tried different seating depths from on the lands to -.005" , -.010"and and then tried some at .020" shot of the mag box which is a "O" give of 2.952" All have shot good but much to my surprise the ones that are 2.952" or .108" off the lands are the ones from the last test and are shining. There also seems to be a bit less pressure there. I will see how it goes and if I need to seat closer will install a wyatts mag box with a .110" more room.

I am shooting the hunting VLD with the J-4 jacket. My steel plate is just a piece of 1/2" steel, nothing hard for sure. But I am still amazed the 180's from this rifle were leaving noticeably deeper dents than a 210 VLD from a 300 win with the J-4 jacket also.

Jeff

 

[DMP25-06]

Hello Broz ,
I know that this thread is over 8 years ago , but I have read each and every post ( all 49 pages ) with great interest . So much so that I would like to have 7mm - .300WM built for me . If I may ask of you, if you know , who built the chamber reamer , and what are the specifications of this reamer that was used to cut the chamber of your rifle ?
It really appeals to me , especially the fact that the cases DO NOT have to be fire-formed , just run .300 Win. mag cases through my Redding .300WM neck bushing sizing die to down-size to .284 ( maybe in 2 steps ) .
In your opinion , would you recommend having the throat set with sufficient free-bore to be able to load and shoot the new Berger 195 gr. bullets , as well as Hornady 180 gr. ELD-M bullets , and especially the Berger 180 gr. Hybrid Match bullets ? Could 1 barrel with a twist rate of 1- 8.7" , or 1- 8.0" , work well with these 3 different bullets , or should I just choose 1 of these bullets to work with ? What would you suggest ?
Thank You ,
DMP25-06

 

[FURMAN]

View attachment 105679 View attachment 105678 View attachment 105677 I know the last reply to this thread was awhile back. I did a 35 degree shoulder version of the 7mm-300 Win Mag with minimum case taper. I had the reamer done years back and some of the heavier high BC bullets weren't in play back then. My chambering has .188 freebore. I had a Wyatt's extended box installed and went with a 28" Schneider R5 Barrel. I want the rifle throated for the Hornady 180gr ELD-M. I want the bullet/boattail junction just slightly above the the shoulder neck junction when seated. Anyone have any thoughts or expirience on a ballpark for freebore to accomplish this? I'm going to send it to Karl Kampfeld to have the throat extended. I know I can send a few inert cases with a bullet seated where I want it but I don't know if that would handi cap me for other bullets. I guess I'm looking for a happy medium across the board freebore, if that's possible.

Based on numbers for my straight 7-300 reamer made for 180 hybrids and comparing to 180 ELDMs I have on hand I would add another .050-.080 and I would error on the longer side. My reamer has .200 freebore. .280 would be great for the ELDMs and good for many other 180s including HVLDS. The Hybrids would be in the neck quite a bit but would most likely still be fine. 175 Elite Hunters and ELDXs would be fine as well.

 

[FURMAN]

Hello Broz ,
I know that this thread is over 8 years ago , but I have read each and every post ( all 49 pages ) with great interest . So much so that I would like to have 7mm - .300WM built for me . If I may ask of you, if you know , who built the chamber reamer , and what are the specifications of this reamer that was used to cut the chamber of your rifle ?
It really appeals to me , especially the fact that the cases DO NOT have to be fire-formed , just run .300 Win. mag cases through my Redding .300WM neck bushing sizing die to down-size to .284 ( maybe in 2 steps ) .
In your opinion , would you recommend having the throat set with sufficient free-bore to be able to load and shoot the new Berger 195 gr. bullets , as well as Hornady 180 gr. ELD-M bullets , and especially the Berger 180 gr. Hybrid Match bullets ? Could 1 barrel with a twist rate of 1- 8.7" , or 1- 8.0" , work well with these 3 different bullets , or should I just choose 1 of these bullets to work with ? What would you suggest ?
Thank You ,
DMP25-06

I would do an 8 twist. I personally do not feel the 195 can be driven fast enough with a temp stable powder to make it worth the time. I would stick with 180s. Also in my limited experience with the 180 ELDM it could not be driven fast enough to make the bc outrun the 180 hybrid which I could run another 50-100 fps. My reamer for the straight 7-300 is on file at ptg.

 

[Gord0]

Hello Broz ,
I know that this thread is over 8 years ago , but I have read each and every post ( all 49 pages ) with great interest . So much so that I would like to have 7mm - .300WM built for me . If I may ask of you, if you know , who built the chamber reamer , and what are the specifications of this reamer that was used to cut the chamber of your rifle ?
It really appeals to me , especially the fact that the cases DO NOT have to be fire-formed , just run .300 Win. mag cases through my Redding .300WM neck bushing sizing die to down-size to .284 ( maybe in 2 steps ) .
In your opinion , would you recommend having the throat set with sufficient free-bore to be able to load and shoot the new Berger 195 gr. bullets , as well as Hornady 180 gr. ELD-M bullets , and especially the Berger 180 gr. Hybrid Match bullets ? Could 1 barrel with a twist rate of 1- 8.7" , or 1- 8.0" , work well with these 3 different bullets , or should I just choose 1 of these bullets to work with ? What would you suggest ?
Thank You ,
DMP25-06

It's my understanding that Broz has gotten rid of all his 7-300's and went to 300wm, and recently a 30 nosler. He's not on this site much anymore, but can be found on longrangeonly.com

 

[Left Hand Dave]

Smack,
is your stock the HS Precision Sendero or Sporter and what is your barrel contour.
Dave

 

[smack]

The stock is is a B&C Alaskan TI. The barrel contour is 3-1/2

 

[Trooper21986]

So how much do I stand to "lose" with a 26 inch tube ? Already got one , can't see a reason to go longer , yet !