7mm practical- who can do the work?
- Thread starter Archibald
- Start date
RJ
So Archibald HOW’s the project going
RJI am waiting for my doner rifle to show up. I still intend on going 7-300 win mag or 7 Practical. Despite the many comments suggesting something otherwise, it's just the way I want to go with it.So Archibald HOW’s the project going
Purchasing a larger magazine box and follower and milling away a portion of the action and bolt stop are within my skill set. I have a pre-64 (1941 pre-war) 300 h&h, as well as a recent 375 h&h Alaskan to compare the magnum action to the "classic" that I have en route.
I had a PM with a recommended gunsmith, I'll give him a call this week. I'll check back in here when I have an update, and probably snap a few photos for you guys along the way.
Stay with it Archie 
RJ
RJI once had a 7mm Yukon, which is very similar to what you are building. The neck was very short but it was very accurate and effective. It was built off a 300 Win mag action. Perhaps it’s because I see the value in some of the old ways, but I kinda like a magnum rifle to have a belt, it takes me back to my young days.
Keep on with your project, I’m am excited to hear more. I believe KS arms would be an excellent choice to do the work.
Keep on with your project, I’m am excited to hear more. I believe KS arms would be an excellent choice to do the work.
Here is the process of conversion. You will have to copy and paste the links. Direct linking here is the worst.
http://echolsrifles.########.com/2020/08/converting-30-06-to-300-h-part-1.html?m=1
http://echolsrifles.########.com/2020/08/converting-pre-64-30-06-to-300-h-part-2.html?m=1
http://echolsrifles.########.com/2021/06/converting-pre-64-30-06-to-300-h-part-3.html?m=1
http://echolsrifles.########.com/2020/08/converting-30-06-to-300-h-part-1.html?m=1
http://echolsrifles.########.com/2020/08/converting-pre-64-30-06-to-300-h-part-2.html?m=1
http://echolsrifles.########.com/2021/06/converting-pre-64-30-06-to-300-h-part-3.html?m=1
Seen a few of Darcy's conversions, very nice work. I have a 70 in 270 Wby I got from him, years back. Nice rifle. Plain. But accurate and never had an issue mechanically. - dan
A photo from the internet:
5 - 7mm-300 win mag
6 - 7mm Practical
7 - 7mm Mashburn
Note the longer necks of the last two and 30 degee shoulder (versus 25 degrees of the first cartridge). I may indeed do a simple 7mm-300 win mag.
My doner action had arrived. It's a mid-late 1990's CRF "Sporter BOSS" in 300 win mag. I compared it to my pre-war 300 h&h, and to the mid 2010's 375 h&h "Alaskan" and it has much more in common with the Alaskan. In fact, the magazine box's are interchangeable between the later two, I'm just going to have to remove the spacer and replace the follower for a full 3.63" length.
the bolt stop needs to be shortened. 300 win mag at bottom. 375 h&h on top:
you can see how much longer a shortened bolt stop will effect the bolt throw. 300 win mag on right, 375 h&h on left:
and the ejector needs to be modified. 300 win mag:
375h&h:
I won't need to mess around with opening up the mag well, as the 3.63" (internal dimesion) magazine works well for the 375 h&h so it'll work for my purposes as well:
I will open up the top of the receiver (middle) towards the rear by .25" to match the 375 h&h Alaskan (right). That's basically removing metal until I reach to where the back of the first screw hole is on the rear bridge.
Note the pre-war 300 h&h model (left) and its huge opening made during a pre-scope era, but loading from the top isn't popular with scoped rifles:
I'm going to remove the barrel later this week so that can get to work with my mill. I should invest in some carbide bits as I think the rear of that receiver is going to be HARD!
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Well Archie your certainly putting ur time in on this one 
RJ
RJJim - I removed the barrel today, and I'm looking forward to getting to work. I may have to stall progess for awhile due to the cold weather in Regina this week and I can't get out to work in my unheated garage.
This level of bubba gunsmithing may require a little more sophistication than running a dremmel in my kitchen, and I would prefer to use a mill.
This level of bubba gunsmithing may require a little more sophistication than running a dremmel in my kitchen, and I would prefer to use a mill.
I compared the bolt stop and ejector on three rifles, and replicated the 1990's rifle parts to be the same as the 2010's Alaskan. After a few minutes on the belt sander, with a bucket of water to cool down the steel (as to not allow it to get hot), I then finished up with a small file. The result worked as expected, and now the bolt throw is longer (the same as the Alaskan) and the ejector works great as well.
I had to account for the difference in the hole placements on the bolt stop, as the Alaskan's part was longer so I referenced the arm/lever as the place to take measurement. Oddly enough, the pre-64 rifle's bolt stop (300 h&h) is relatively close to the same dimensions as the 1990's rifle (300 win mag) so once again it was of little use in reference for modifying the parts.
I had to account for the difference in the hole placements on the bolt stop, as the Alaskan's part was longer so I referenced the arm/lever as the place to take measurement. Oddly enough, the pre-64 rifle's bolt stop (300 h&h) is relatively close to the same dimensions as the 1990's rifle (300 win mag) so once again it was of little use in reference for modifying the parts.
Hey Archie 
whats going on ? RJ
whats going on ? RJI resized some 300 Win Mag brass using the 7mm Rem Mag full length die to make a standard 7-300 Win Mag wildcat cartridge, being careful to not bump the shoulder back any further than the 300wm full length die. I have to make a decision about the cartridge OAL, please continue reading.
- I removed the spacer in the factory magazine box and now it's internal dimension is 3.630". A bullet seated to 3.600" OAL fits nicely inside.
- There is a Wyatt extended magazine box that has an internal dimension of 3.825", and if I further modified my action that would fit and I could seat bullets to 3.800" OAL.
-I assume any capable gunsmith could ream the freebore for whatever bullet I request and with the desired jump to the lands that I request. There would be a little more case capacity potential with a longer magazine, but I want to know if there a noticeable deficiency in seating the 180gr Hornady ELD-M at 3.60" vs 3.80".
In your opinions, would I gain anything by utilizing the extended magazine box? In contrast, is there any disadvantage of going that direction?
- I removed the spacer in the factory magazine box and now it's internal dimension is 3.630". A bullet seated to 3.600" OAL fits nicely inside.
- There is a Wyatt extended magazine box that has an internal dimension of 3.825", and if I further modified my action that would fit and I could seat bullets to 3.800" OAL.
-I assume any capable gunsmith could ream the freebore for whatever bullet I request and with the desired jump to the lands that I request. There would be a little more case capacity potential with a longer magazine, but I want to know if there a noticeable deficiency in seating the 180gr Hornady ELD-M at 3.60" vs 3.80".
In your opinions, would I gain anything by utilizing the extended magazine box? In contrast, is there any disadvantage of going that direction?
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Look what I roughed out with just a few files and a couple of evenings. This is not a finished job, so please don't be cruel in your review. I feel compelled to post the update for Remington Jim who seems interested and is keeping me motivated, lol.
Lower rifle is now a magnum action, and matches the upper rifle (375 h&h Alaskan). Obviously, I'll clean this up a bit more, but here's a preliminary look. Take note of the longer bolt throw, as previously the bolt would stop when the front of the extractor ring was flush with the rear bridge.
I should get a magnum extractor, which is slightly longer than the one on this standard length bolt. With the modification to the rear bridge, the extractor can binds when opening the bolt, but in fairness I have not cut the relief inside the bolt pathway on the upper side of the rear bridgem. That'll probably mitigate that problem.
Here are the modified parts. Missing from the photo is the remington 700 long action magazine follower (shortened to fit this magazine) and its spring. So far the rifle works great while cycling a full magazine of dummy rounds, although I may have to take a bit of material off the back of the feed rails so the rounds don't get hung up so easily near the rear.
Lower rifle is now a magnum action, and matches the upper rifle (375 h&h Alaskan). Obviously, I'll clean this up a bit more, but here's a preliminary look. Take note of the longer bolt throw, as previously the bolt would stop when the front of the extractor ring was flush with the rear bridge.
I should get a magnum extractor, which is slightly longer than the one on this standard length bolt. With the modification to the rear bridge, the extractor can binds when opening the bolt, but in fairness I have not cut the relief inside the bolt pathway on the upper side of the rear bridgem. That'll probably mitigate that problem.
Here are the modified parts. Missing from the photo is the remington 700 long action magazine follower (shortened to fit this magazine) and its spring. So far the rifle works great while cycling a full magazine of dummy rounds, although I may have to take a bit of material off the back of the feed rails so the rounds don't get hung up so easily near the rear.
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Fast twist, and 3.8". My next 7 stw will have that combo. - dan
stevesummit
CGN Regular
- Location
- spruce grove
We (EM Precision) have that reamer. I would echo other thoughts and suggest the 7PRC, but if you want a Practical we can do a Practical.
