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Longer COAL on Rem 700

kyotekiller25

Sergeant of the Hide
Full Member
Minuteman
Jan 31, 2021
298
213
USA
I was doing some tinkering around with my Rem 700 in 7-300 win mag earlier today with bullet measurements. The smith who built the rifle didn't really throat it properly unfortunately. On the flip side of that, its also probably the best shooting rifle I've ever owned. When I had it built 10 years ago, my plan was to shoot the 162 amax from the 28" Bartlein 9 twist. There were no really good high bc bullets other than the 168/180 bergers back then. Anyway, the 162 amax hit the lands at around 3.450" which is very short, and the bullet is seated way down in the case. I shot them for 7 years or so before finally switching to the 180g ELDMs. These hit the lands around 3.5" But again, these are seated very very deep in the case. The dreaded "donut" got me thinking well just how far out do these 180s need to be seated to not be in that area? I haven't experienced donut issue yet from the Nosler brass that's been fired about 10x, but just got me curiois anyway. From my crude measurements I'm coming up with around 3.750" which is a tad bit longer than you can fit, feed, and function through the factory mag. I'm well aware of Wyatts extended box mags as I had to have one for my 338 EDGE/300g SMK build years ago. I think that allowed me to get to 3.8" or so. I'm just wondering if that is the most cost effective way to get a longer COAL? I have a McMillan A5 stock, but it's just inletted for the standard BDL bottom metal. Would it be worth it to convert to M5 AICS mag setup? Can a guy install the Wyatts mag box himself? The M5 detach mag set ups are pretty spendy from my limited research. Could I have a smith go in and just ream out the throat to the new desired length? And if so, could that potentially be a risk on ruining how it shoots?Here is a couple pictures to represent what I'm talking about with the bullet lengths.

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Maybe i missed it, but why do you want to change it? .65 isn't bad for 10X unless you are a BR guy.
For a PRS, NRL, or just a hunter, most people chase this...…especially for a screamer like the 7-300 is.

but to answer your question,
1 a good gunsmith should be able to lengthen your throat or
2 you can just chop the end and have it completely rechambered. You might loose 2 inches but the velocity loss should only be about 30-60 fps really

If you lengthen, it should increase case capacity and lower pressures, so I would develop a new load or just test your old and rock out



FYI 10 years ago their were a lot of higher and great bullets out at the time, i.e. Berger 180 gr Hybrid was out.....were you just getting into LR shooting really? I'm just curious and not trying to offend at all
 
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