Starting over with 300 win

[miningshawn]

As the title says, I'm starting over with my 300 Win. I have:
Lapua Brass (unicorns exist!)
H1000 (8lb)
Berger 215 Hybrids
I am ordering a barrel and trying to find which reamer to use. I would like to seat further out, AOL around 3.640 to 3.650, to avoid too much intrusion into the powder chamber. Barrel length will be 28" with a "heavy Palma" contour. Does anyone have a winning reamer they would like to recommend?

I don't mind touching or jumping - but I don't do "jammed".

 

[AckleymanII]

How about a gunsmith that knows how to use a uni throater? Send him a dummy round with a bullet at your Magic length?

 

[CNC-Dude]

I shoot the 215g Bergers in my WinMag and they seat quite a bit longer than what you are planning. Mine is a factory Savage 110 Tactical.

 

[6fatrat]

You should consider a light palma contour instead of the heavy contour, 1/10 twist.
Steve Bair

 

[miningshawn]

You should consider a light palma contour instead of the heavy contour, 1/10 twist.
Steve Bair

Why do you suggest that? I've always heard that a heavier barrel was typically a more accurate barrel. I do agree on the 1:10, I have given some thought to a 1:9 but do not expect to be shooting much above 225 grains.
Thanks!

 

[miningshawn]

How about a gunsmith that knows how to use a uni throater? Send him a dummy round with a bullet at your Magic length?

Didn't think about that... I have been building wildcats and I am used to just getting a reamer. It isn't the money, it's the incredibly long wait times that get me down.
Thanks!

 

[Walt Krafft]

I went down this rabbit hole a couple of years ago. PTG has a reamer that was designed by Chris Kyle and a shoulder headspace gage. Had good luck with this combination. I tried 5 different reamers if I remember right.

 

[FeMan]

Make sure you don't overlook the base chamber measurement and get that right. I've seen too many custom belted mag chambers that are too tight at the 0.200 line where even my collet die couldn't get them sized down enough.

 

[miningshawn]

Make sure you don't overlook the base chamber measurement and get that right. I've seen too many custom belted mag chambers that are too tight at the 0.200 line where even my collet die couldn't get them sized down enough.

Exactly. One of the reasons I am looking for a winning reamer is to nail the chamber dimensions. I haven't dealt with case head separation in a belted magnum yet, but it has been oh so close.
It only took 4 firings at 75gr of H1000 in the old chamber to stretch the brass out to unusability!

 

[k80skeet]

Exactly. One of the reasons I am looking for a winning reamer is to nail the chamber dimensions. I haven't dealt with case head separation in a belted magnum yet, but it has been oh so close.
It only took 4 firings at 75gr of H1000 in the old chamber to stretch the brass out to unusability!

Unfortunately the belted Mag head space on the belt not the shoulder and for some reason (I expect it is cost) and most cases give out at the base before the neck. Even when annealing is done every time. It seems to be the nature of using a belted case. Some cases are better than others and do crack at the neck.

 

[boltfluter]

I used to own a very nice 300WM in a Browning A bolt. Awesome shooter! Never lost a case with that rifle. What I did was necked up to .338 and then necked back down and set a false shoulder to headspace on. I have no clue where the belt was and could care less. Worked like a charm.

Paul

 

[dragman]

I am putting the finishing touches on one right now that sounds similar to what your making.
I did palma contour 9 twist Krieger 28"
Rhian Mantha/Broz jgs reamer
I can set the 215's out to touch and still feed them from the large wyatts box. I can get the 230's to touch and "almost all" of the bearing surface is in the neck.
Still feeds perfect gun came in at 11.5lbs.

 

[6bra1k]

why a 215 in a 300 win mag
i would look at a 230 in a 10 twist and then set up a dummy round and use a br reamer and throat to fit

 

[ebb]

300WSM or 30 RSAU they don't have belts and have none of the pitfalls associated with belted cases. Some of the new ideas are actually better, not all but some.

 

[Hammer101st]

Exactly. One of the reasons I am looking for a winning reamer is to nail the chamber dimensions. I haven't dealt with case head separation in a belted magnum yet, but it has been oh so close.
It only took 4 firings at 75gr of H1000 in the old chamber to stretch the brass out to unusability!

When i had my 7RM built my gunsmith only spun the reamer in so far that my cases only grew .004 and the .200 line is 1thou under sammi spec. He had his own reamer made like this from the specs off of a peterson brass 7rm case i have 4 hot reloads on my brass and i have not had to resize the webs yet