300WM Headspace question

[squirrel_slayer]

Hello, Wanted to ask a quick question about the belted magnums. I know the new trend on precision built 300 win mags is to headspace on the shoulder rather than the belt so my question is this as simple as using say a no go gauge rather than a go gauge and then sizing the brass accordingly? or do you have to get a special reamer? My brother and I are talking about going halves on a reamer between the two of us we want to do 3 barrels and were going to have it throated for 225 hornadys.

[Hotolds442]

There's roughly .005" between the go and no-go gauges. Set the barrel with the go gauge as you normally would and adjust your sizing die to barely bump the shoulder rather than full- length resizing. Brass fired in that chamber and neck sized only, or bumped minimally, will now headspace on the shoulder and the belt will have that .005" clearance. Since there is some spring back, I would (and do) neck size only.

[Robinhood]

You will get opinions from both camps. In my neck of the woods the guys cutting chambers space off the belt and size the brass to the chamber after the first firing. The belt dimension does not move or change and is a constant, the neck to base dimensions vary from rifle to rifle. Cant explain why there is not more of a standard.

Vanden Burg Customs single pointed the belt dimension on one to put the shoulder of the reamer where he wanted it( I guess the reamer was long)

Edit: My PTG was .003 between the go and no go. ( I posted .002 but checked and it was .003)

[Hotolds442]

I just used the.005" as an arbitrary number, since it's a lazy Sunday I didn't feel like looking it up.

[FW Conch]

Hotolds442 has nailed it IMO. The same is true for belted cases, rimmed cases, rimless cases, rebated rims, etc. Nobody is going to convince me that I need or should want headspace in my rifle reloads. I do My bumping when the reloading is finished ;-)). That's where I "camp"! :-)

[squirrel_slayer]

so you want it to headspace on the belt and fireform it and just neck size?

[FW Conch]

Yes. That's what I do. When the brass is fire formed, then it head spaces on the shoulder. I neck size with a LEE collet neck die. I get 10 reloads before I have to full length resize and push the shoulder back to zero. For those who run max loads or more, you may not make it to 10. This is just me, but why would I want to induce "slop" in to my reloads, loading for a bolt rifle? If a case is not going to chamber, I find out way before I reload it.

As far as the 225grn pills, you could seat them where they need to be and just use a little faster powder, if they go a little farther back into the case. Having a custom reamer made seems an expensive step unless your getting serious into competition?:-)

[Robinhood]

so you want it to headspace on the belt and fireform it and just neck size?
You can still full length size, just set the die to bumb the shoulder a couple of thousandths. You need a way to check the dimensions like a Hornady Case Head Space gauge.

[squirrel_slayer]

Yes. That's what I do. When the brass is fire formed, then it head spaces on the shoulder. I neck size with a LEE collet neck die. I get 10 reloads before I have to full length resize and push the shoulder back to zero. For those who run max loads or more, you may not make it to 10. This is just me, but why would I want to induce "slop" in to my reloads, loading for a bolt rifle? If a case is not going to chamber, I find out way before I reload it.

As far as the 225grn pills, you could seat them where they need to be and just use a little faster powder, if they go a little farther back into the case. Having a custom reamer made seems an expensive step unless your getting serious into competition?:-)

Ok didn't realize it was that simple. we were looking at the a191 reamer as it has a long throat. anybody know where the 225 hornady's end up with this chamber? I bought my first lee collet die a few months back and now I kick myself in the ass for not trying one sooner (read about them 6+ years ago just never pulled the trigger)

not for competition just good ol fun. were starting to get into the ELR game and it seems like a 300WM with 225 hornadys is about the cheapest way into the game. making consistant hits at a mile is a personal goal i'd like to achieve. I find I can have as much or more fun with 40 rounds behind a bolt gun at distance than I can with 3 times that running a carbine up close.

[FW Conch]

I don't shoot a mile, and I don't know how far You currently shoot. But how ever far that is, I would think You would want to work your way out from where You are? And I think it would be good to start with the gear You currently have on hand? You will learn as You progress what You need and want. In the beginning, You may be happy to "hit" a 4'x8' sheet of plywood, at a mile, but that won't last long ;-)).

As far as headspace, and sizing, for Me the only purpose of a new rifle case is to be fired in my rifles chamber. Now it has value to me. I measure my fired brass by chambering it in my rifle and closing the bolt. If it passes that test, I reload it. If it fails, won't chamber, I FL size it so that it will again chamber. For Me, anything more than this would be overworking my brass, and unnecessary.

On Your way to a mile You may choose to do things differently? Have fun on Your journey! ... Jim

[Robinhood]

Good post FW.

[FW Conch]

^ You to "Brother" :-) ^

[squirrel_slayer]

agreed! right now the furthest i've shot is 954yds (was in the bushes) and that was with a .308 on a 2/3 ipsc steel. I also have a 20" gong and thats what I plan to engauge at a mile but as you stated I have to work my way out there. the .308 gets exponentially harder after the 800yd line (about the same as shooting a 22lr a 200yds and moving to 250 in my experience) Last time we were out we scouted a spot that will easily yield our goal. I have a dueling tree that we setup at 400 and it was a hoot with the .308's we ran out of ammo before moving to the 600yd line like we planned. so thats the goal next time out. it has 6" plates. I've been fighting myself to not creep to the dark side of 6.5's and it's hard! a 260 would be a great bridging cartridge.

[FW Conch]

Beware the dark side My Brother! My BIL got into 1,000yd competition last couple of years. He's been to the Williamsport clinic twice now. He just put $4,000 into a 6Dasher build, Batt action, yada yada. Along the way, he found a 300WSM, just like his build, for $2,500. He couldn't pass it up. He's going to use it for his "wind" rifle. Looking at March scopes now. I guess the Night Force didn't hack it? He had a really great shooting 6BR that he had set back and rechambered with the same reamer used for the new build, and the custom dies. He's going to use that for his fireforming rifle. My Sister asked Him what He was going to do when He retires. He's so deep into OCD reloading, that won't be a remote problem. Weighing, sorting, measuring, etc., etc. He just got into meplat uniforming and pointing. Increases the BC enough to raise the POI 4" at 1,000yds You see. He was recently in a competition, shot 2nd, 1.9" group at 600yds, first place was 1.1". His lay out is starting to exceed my living expenses :-((

The "Bug" can bite very hard! ;-))

Oh, I forgot to mention the Ransom Rest!

[squirrel_slayer]

ha ha. yeah I can see that happening in time. I do enjoy reloading myself. a hobby that feeds another hobby. I'm just getting back into the sport myself. my poor safe was hemmorrhaging guns several years back. (went from making good money, no debt aside from a mortgage and a car payment to having the carpet pulled out from under my feet when the economy tanked to getting married and starting a family within a year and a half's time) but we made it, the kids are healty, wife is happy and finally able to enjoy the little things in life. I actually had Apache build me a beautiful .338 edge barrel years back and that was my ticket into the game but it was unfortunatly one of the casualties as well as a lothar walther .260 barrel I had. both never got to burn powder (during the powder shortage of 2013 lol)