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7mm on the 300 winchester
- Thread starter ann brezinski
- Start date
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WildRose
Well-Known Member
I always think in terms of either SAAMI Specs or those of the most popular WC's but I rarely mention it. That way I'm thinking in terms of relative equals.
Johnny blade
Well-Known Member
Thank you for your reply, I was just curious if anyone new. Not something I would try just to see if it worked. Might could hurt a little.
lancetkenyon
Well-Known Member
Not at all. Huge case dimension differences.
I have a new 7 Practical reamer and 7 Mashburn reamers with short freebore, Uinthroater to cut freebore to desired lengths.
The Mashburn is what the 7 Rem Mag should have been, sharper shoulder angle with a long neck. The Mashburn will run the 160-168g bullets at 3200 with no case issues on a 24" barrel, and upwards to 3300-3350 if you want to push the pressures on tough brass in a 26" barrel.
Manson has the 7 Practical dies, 7 Mashburn dies are scarce as like chicken lips.
The advantage of the 7mm based on the 300 Win is the availability of brass, and now very good brass. I have some Lapua 300 Win that I am going to spec out a reamer on, and see if the brass matches the dies I have on hand. My first 7 STW reamer, I spec'd out on Win 7 STW brass and designed the web that was .0023 over the web dimension at the .200 line on the web....way too tight. That dimension should have been .0035 over the Web dimension at the .200 line on the web, and I ended up with a 7 STW RCBS small base sizer to make up for that mistake.
The Mashburn is what the 7 Rem Mag should have been, sharper shoulder angle with a long neck. The Mashburn will run the 160-168g bullets at 3200 with no case issues on a 24" barrel, and upwards to 3300-3350 if you want to push the pressures on tough brass in a 26" barrel.
Manson has the 7 Practical dies, 7 Mashburn dies are scarce as like chicken lips.
The advantage of the 7mm based on the 300 Win is the availability of brass, and now very good brass. I have some Lapua 300 Win that I am going to spec out a reamer on, and see if the brass matches the dies I have on hand. My first 7 STW reamer, I spec'd out on Win 7 STW brass and designed the web that was .0023 over the web dimension at the .200 line on the web....way too tight. That dimension should have been .0035 over the Web dimension at the .200 line on the web, and I ended up with a 7 STW RCBS small base sizer to make up for that mistake.
jimbires
Well-Known Member
I bought my 7mm mashburn super mag , forming dies here .
www.ch4d.com
Caliber List : CH4D
Browse the largest selection of reloading die calibers in the world!
Azrael
Well-Known Member
I'm not telling you to do it; but a 7 Rem will fit in a 7-300 Win or STW and head-space on the belt. The brass will be a write-off, because the shoulder will move so far forward that the neck is mostly gone on the 7-300 Win and completely gone on an STW but it's safe enough. I did some playing with my 7-300 Win (straight neck down) and I could hit my 500 yard IPSC silhouette with 7 Rem ammo without touching the turret. 'Course it was low, but I wouldn't want someone shooting at me with that combo.
You can shoot 300 Win in 300 Weatherby without consequence, whether you can hit anything with it is a different matter. You never heard it from me; but there are times when some ammo is better no ammo.
tjm1534
Well-Known Member
I have 2 284 Jarrett rifles built by Kenny about 2006 and I love the cartridge.Both of them have 25 inch barrels without brakes.It is generally about 150 to 200 FPS faster than a Rem mag and mine have Kwik klips so I can take the clips out easier in Canada with thick gloves on .You can't run a kwik klip with an STW,it's too long. Love those Jarrett rifles. They shoot tiny groups.
Johnny blade
Well-Known Member
I'm not really sure how to respond to what you are saying other than I like my Stws and my face more than to try and shoot 7 mag sounds out of my Stw. Maybe it would have been better are how close the 7 practical and 7 mag are. My inquiry was because I had never heard of the 7 practical.
Azrael
Well-Known Member
The 7 practical isn't as practical as just necking down the 300 win without any other changes; and Nathan is quick to admit that if he had known that the 7-300 was already an on the shelf item he wouldn't have bothered. A squarer shoulder isn't going to change the world much.
My 7-300 Win shoots the same chart as the only STW on my racks that I'm useing the same 180 VLD. It also does it using 5 grains less of the same powder, with 2 inches less barrel. The lands still haven't migrated in 1500 mostly field on game shots. That might fit in with my belief that there is a practical limit to how much powder you can reasonably push down a 7mm hole, but I can say that I have 4 STWs that aren't going to to be rebarrelled the same way and I was shooting them since 89.
Gotta ask you something; Are you scared to shoot a 22 short in a LR chamber? A 2 3/4' 12 gauge in a 3" chamber? Do you have nightmares about making 458 Lotts out of 375? Have you ever formed AI cartridges?
Hey; at least you're shooting an STW. can't be all bad.
Johnny blade
Well-Known Member
Not sure the point of your question but I have fire formed Stw brass at times out of whatever I could find at the time same with my 308 Norma.
As I recall, Nathan had extensive knowledge of a "straight" 7-300 being on the shelf due to a lengthy conversation with Broz on this site. Nathan chose the 30* shoulder for whatever reason and spec'ed it in 2-3 generations if reamers. Were it me I'd have gone 35-40* but he wanted the necks to grow. Reamer specs are .299" to allow this. If you have had conversations with him personally I won't dispute your claims. The Practical is a fine cartridge and I own a rifle chambered in it. Forming is easy. Dedicated dies are needed. I did in fact have the throat cut .050" forward to accommodate bullet seating as well as having Shawn and Bob at DE give it the +P treatment. The throat has moved about .0015"/hundred rounds of slow, controlled fire (for the most part). IMO the 7-300 in any of its forms is a winner. It gives up little to the bigger 7's with less wear and tear on equipment.The 7 practical isn't as practical as just necking down the 300 win without any other changes; and Nathan is quick to admit that if he had known that the 7-300 was already an on the shelf item he wouldn't have bothered. A squarer shoulder isn't going to change the world much.
My 7-300 Win shoots the same chart as the only STW on my racks that I'm useing the same 180 VLD. It also does it using 5 grains less of the same powder, with 2 inches less barrel. The lands still haven't migrated in 1500 mostly field on game shots. That might fit in with my belief that there is a practical limit to how much powder you can reasonably push down a 7mm hole, but I can say that I have 4 STWs that aren't going to to be rebarrelled the same way and I was shooting them since 89.
Gotta ask you something; Are you scared to shoot a 22 short in a LR chamber? A 2 3/4' 12 gauge in a 3" chamber? Do you have nightmares about making 458 Lotts out of 375? Have you ever formed AI cartridges?
Hey; at least you're shooting an STW. can't be all bad.
Next time around I'm considering a 7-300 PRC to take advantage of the more modern brass/case profile. I may even AI the darn thing as I single feed regularly, but that's another story.
Azrael
Well-Known Member
You wanted to know what would happen if someone fired 7 Rem cartridges in a Practical and I told you. Thats all.
Lefty7mmstw
Well-Known Member
THIS...
I probably will not build another 7stw if the brass situation remains what it is now. I have several hundred fresh brass that will be enough to end my current barrel. After that it will be a 7x300 or plain 7rem.
You can play with throating all you want but in my mind if you get over a couple of tenths of an inch freebore you are really just building a 1/2 shot out rifle to start with. That said, my short throat 7rum is a pain and I've thought about cutting the throat another couple tenths to be able to use regular load data. I've decided to just keep shooting. In a few hundred rounds I'll bump the load up as the throat wears.
