Stoneypoint Headspace gauge

[Varmint Hunter]

I decided to get a headspace gauge so that I could see just how far the shoulders were moving foward and how far the Redding body die was setting them back. Rifle is chambered in 7STW. Here is what I noticed:

New Rem 8mm mag cases = 2.448"
Cases fired several times = 2.468"
Cases after being run through the body die adjusted tight to the shellholder = 2.458"

Not sure where all this leaves me. Anyone else take these measurements on their 7STW?

 

[Bart B]

Where it leaves you depends on a few other things.

The case is supposed to headspace on the belt. There's only .003-inch spread between GO and NO-GO headspace gages for H&H belted cases. It's been my experience that such belted cases produce best consistant accuracy if the shoulder is set back at least .005-inch but not more than .010-inch to ensure the case headspaces on that belt. Case life will be shortened somewhat by doing this but accuracy sure improves.

If your cases have a tiny step in front of the belt where the body (or full-length) sizing die stops reducing fired case diameter, that step may interfere with the chamber at the same place when the cartridge is loaded. That interference can cause accuracy problems. When I use cases with that step in them, they don't shoot as accurate as new H&H belt type cases. Many other folks notice the same thing.

Few if any body or full-length sizing dies reduce fired case diameter immediately in front of the belt enough to eliminate that step. There's a collet die from www.larrywillis.com that does the trick perfectly. And it'll work on most other H&H type of belted cases.

It's been my observation that belted cases shoot most accurate when all of their body diameters are resized back to almost their original dimensions except for neck diameters which can be adjusted for tension on the bullet. Shoulders should be set back enough to ensure the case headspaces on the belt and not the shoulder.

 

[Ol'Gator]

Bart, do you know if dies from Larry are anywhere to be found? I spoke with him a while back and he said the dies were currently not being produced.

 

[Varmint Hunter]

Thanks Bart - I've got to spend a bit more time taking these measurements into account while observing their effects on accuracy.

 

[Bart B]

[ QUOTE ]
Bart, do you know if dies from Larry are anywhere to be found? I spoke with him a while back and he said the dies were currently not being produced.

[/ QUOTE ]I don't know if they're available. But you can make one like I did years ago back in the 1960's when folks first learned about solving the problem.

Get a full-length sizing die for an H&H belted cartridge that has the same body taper per inch, then toss its decapping rod and what's attached to it. A used one's cheap and works just fine. Then modify it as follows:

1. Cut off the bottom of the die about 1/8th inch above the die's belt clearance recess. The die's inside diameter at that point should be a few thousandths of an inch smaller than a new belted case's diameter immediately in front of the belt; about .510-inch.

2. Then cut the top of the die off just below the shoulder. Now you've got a body sizing die ready to finish.

3. Square up both ends of this body-sizing die then polish them smooth.

4. Slightly radius the inside edge at the bottom and top so it won't scrape brass off a cartridge case as a lubed case goes into and out of the die.

Here's how this body die's used.

1. Full-length size your fired belted cases to set the shoulder back several thousandths of an inch. Don't remove the case lube on them.

2. Remove the full-length sizing die from the press and replace it with your new body sizing die. Screw this die down into the press only a few turns.

3. Put a still-lubed full-length sized case in the shell holder and raise the ram to the top. We'll call this case a pre-sized case.

4. Screw down the body die until it starts to size the pre-sized case a bit. Note the distance the bottom of the body die is above the belt in the pre-sized case.

5. Lower the ram, screw the body down about one more turn, then raise the ram again noting how close the top of the belt comes to the bottom of the body sizing die.

6. Repeat step 5 several times but screw the body die down less until its bottom just clears the belt by a couple thousandths of an inch. Using a magnifying glass may help here.

Note: The objective is to size the case body all the way to the belt; not stop some distance above it. If this body die doesn't size case diameter right in front of the belt to the same as a new case, then you need to cut off a bit more and radius the body die's bottom.

7. When the body die's set, lock it into place.

8. Double-size the rest of your pre-sized cases and you're done.

 

[Varmint Hunter]

One other thing that I noticed:

New Rem cases measured .505" just ahead of the belt
Fired cases measured .515"-.516" just ahead of the belt
Cases sized in Redding body die measured .513" just ahead of the belt. I could not reduce the diameter any more with die adjustment.

Based on my measurements, new Rem brass is quite a bit smaller than my chamber and smaller than my dies will return it to, if there was a desire to do that.

 

[Hired Gun]

Every chamber is different so trying to compare measurements is meaningless. The new brass measurement also means nothing. Your fired brass verses you chamber measurement are the ones that matter. If you dead set on bumping the shoulders back then I would only go a .001-.002 under your actual chamber size. The farther you set them back the quicker you will have a head separation. My dad was big on full length sizing and he would have a separation between 3 to 5 firing on his 7 Mag. It drove him crazy if our handloads wouldn't interchange between our two 7Mags. To deal with it he just threw them away after the 3rd firings.

Once I moved out I now call the shots. All my rifles shoot best with fired formed brass. On belted cases I just ignore the belt. I have belted brass with over 20 firings and they don't ever get tight due to the belt. I haven't bumped a shoulder back in 15+ years. I use Lee Collet dies on everything I can. The only thing they touch is the neck. If you feel you must bump a shoulder back I would do it by feel, just only bumping enough to get them to chamber decent. If your bolt is closing hard you might be a little high on operating pressure. Even my Weatherby's that have very little camming action close easy. A Stoney Point guage head space guage is a novel toy but I have never felt the need for one.

 

[Varmint Hunter]

HiredGun

Actually, I find that the StoneyPoint Headspace gauge allows me to take measurements of things that I was previously guessing at.

I have several sets of Redding Comp Bushing Neck Dies. The body dies were adjusted according to the directions provided by Redding. Now that I have had an opportunity to actually measure once fired cases and cases that have been run through the body die I have noticed that some body dies were not touching the shoulder at all while others may have been moving them back more than necessary.

One at a time, I have been adjusting my body dies to move the shoulders back .002-.003". Previously I was only assuming what the body dies were doing and I assumed wrong.

I do not ALWAYS run my cases through the body dies but it is nice to know what you are achieving when you do.

Still learning after all these years. /ubbthreads/images/graemlins/grin.gif

 

[LRHWAL]

I'm in the process of ordering a Stoney Point headspace guage. I posed some questions about belted mags some months back as I recall. I'll see if I can find it and post a link; some of the comments may be of interest.

Varmint Hunter, do you adjust for shoulder setback with the gauge after the first firing of new brass (i.e. make the adjustment on once fired), or after a couple of firings?

I recall either Redding or Sinclair providing a description of the "size by feel of bolt close" method (with firing pin removed etc.) suggesting using cases fired several times.

Your thoughts on this are appreciated.

I'm pleased this thread is getting into this.

Thanks.

Wim

 

[Varmint Hunter]

The headspace gauge is new (for me) so I'm just experimenting at this point. Brass shot several times at various pressures will probably confuse things at this point.

As a base line, I have been measuring new unfired brass, once fired brass (unresized) and body sized once-fired brass.

Many things have come to light and now I'm wondering why I waited so long to buy a headspace gauge in the first place. /ubbthreads/images/graemlins/smirk.gif

 

[jb1000br]

Bart -- I think you forgot a zero...

5-10 thou shoulder bump /ubbthreads/images/graemlins/shocked.gif

more like 1-2 thou

i had Lapua 308 cases separate at the web on the 7th firing and i was moving the shoulder 5thou each sizing.

VH -- use a several times fired case as your baseline...not 1x fired.

JB

 

[Bart B]

[ QUOTE ]
Bart -- I think you forgot a zero...
5-10 thou shoulder bump /ubbthreads/images/graemlins/shocked.gif
more like 1-2 thou
i had Lapua 308 cases separate at the web on the 7th firing and i was moving the shoulder 5thou each sizing.

[/ QUOTE ]I was almost right. Thanks for bringing this to my attention.

I've found that belted fired case shoulders need to be set back 5/1000ths to 7/1000ths (not 10/1000ths) of an inch or to about where new cases are relative to chamber headspace. This ensures belted cases headspace and stop moving forward from firing pin contact at the belt, not the bottleneck shoulder. Every time I've tested H&H belted cases for accuracy with the shoulder making contact before the belt does, accuracy ain't so good. New cases shoot more accurate than fired cases full-length then double sized setting their shoulder back only "1-2 thou" in my magnums as you suggested.

Rimless bottleneck cases are different. They gotta headspace on the shoulder. Their shoulders should be set back 2/1000ths to 3/1000ths (.002 to .003) of an inch from their fired position. Doing this with a .308 Win. case made by Winchester and with a full-length sizing die reducing body diameters about .003-inch has got me at least 60 loads per case cause that's the most I ever reloaded one. Others doing this get 80 to 100 reloads per case. (Anybody ever get that many reloads on any other make case?)

Setting fired rimless bottleneck case shoulders back more than about .003-inch will indeed shorten case life. I'm convinced this is why so many folks like to neck-only size or partial-neck size their rimless cases. They set the shoulder back way too far and don't have/use a case headspace gage to measure exactly what they're doing. They over do it full-length sizing and start neck-only sizing and claim better accuracy by doing so. They're right. But if they just got a case headspace gage (RCBS Precision Mic, Stoney Point, there's some that's been available someplace since the 1960's) and used it properly to set up their full-length sizing die, wonderous things would happen.

 

[Hired Gun]

Bart, I've seen you post this stuff on the belted cases before. It is normal accepted practice and my personal experience that fire formed brass consistently presents the bullets centered in the bore and the case head in close proximity to the bolt face for consistent primer ignition. In bench rest they even cut chambers and necks undersized to tighten the fits up even more. This theory applies to all bottleneck cases. Now I have to ask, why is a belted case is not going to benefit from the same time proven methods?

Please also explain how you get any case life at all if you keep pushing your belted cases back so far that they have to head space on the belt alone.

In your last post you referenced people going to neck sizing and claiming improvements in accuracy. I fall in that group. I don't even own a full length die for my 257Wby. With fired Lee Collet neck sized brass it shoots in the .2s". With new brass it shoots ¾ to 1" with the exact same load. What do you think you could gain on this one with your method?

 

[LRHWAL]

Ok, so my previous post that I referred to was on a different forum, Oops!

Yes, I was also under the impression that several times fired was preferred for micing, but I wasn't sure. Thanks.

I've comes across a few interesting discussions and there seem to be a bunch of different opinions on how much to resize. Reference is made to the guys at Sierra and all sorts of long range and bench rest records and practices over time.

I don't have the personal experience to comment, but the general responses seem to focus around full length sizing being best (although there seems to be some use of "full length" to include even bumping the shoulder just a couple of thou as opposed to neck only). Part of the argument against neck sizing is based on precise orientation when chambering a neck sized only cartridge (i.e. you can never index it identically to the previous firing).

From what I can gather things have gone (and still do?) in circles in the neck size, full length size, shoulder bump "is best" argument and it makes me wonder whether there's a definitive answer.

Bench rest accepted sizing practice has also moved about quite a bit from what I can establish and the records seem pretty awesome throughout this.

So I'm looking forward to the responses from those way more experinced and informed than I am, but I'm not expecting to see a clear winner here.

WL