Headspace issue 6.5-284

[4xforfun]

I just got a new 6.5-284 bbl back from the smith. I ran 3 rounds through it for break-in with no issues. I started taking the inital measurments that I usually take before I start the load development process. I found that the new Lapua brass has .007 -.009 headspace. Now, to be honest, I use scotch tape on the back of the cases to test, but I used 4 or 5 layers on the brass. I measured the thickness of the tape with my caliper.....it is .002 per layer.. On about half of the bass the bolt (without the firing pin assy) closed easily ...with no measured resistance with .006 tape and would not close on .008 tape. I figured that at .007 headspace +.002 on the other half for .009. I have been using scotch tape forever..has worked well for me over the years. I know it is not the same as steel/brass shims!!


I talked to my smith wondering if it could be attributed to the whole 6.5-284 Win vs Lapua, Vs Norma thing. He said that the headspace on all of them were the same as far as he knew. He also guarinteed that he sent it out of the shop like all of the others......bolt will close on the go gauge with a .002 shim, but will DEFINATLEY NOT CLOSE with a .004 shim. He calls it .003 headspace...and I believe him without a doubt!!!!

Now, again to be honest.....I did tweek the brass. I always iron out the necks with my Sinclare expander. I use the E26 expander and then neck size the brass with the proper bushing (in this case a .294....chamber is .297) before they ever see powder.

Is this normal headspace for this cartridge? There is no possible way I messed things up when I Ironed out the necks. Is it possible I got some out of speck brass?

The simple fix for me would be to expand the necks to .277 and size them back down ..ie false sholder......like a Dasher. or..get new brass.

 

[280man]

Why not just jam the bullets tight in the rifling?

 

[Hengehold]

Why not just jam the bullets tight in the rifling?

+1

Trevor

 

[dkhunt14]

I would just jam the bullets and use a lot of tension. I would size the neck past where the pressure ring is. I fired hundreds of Dashers and formed them good. Lately it seems a lot of factory brass is short on headspace. Most guys don't notice because they just load them and shoot. They don't measure them. Matt

 

[4xforfun]

I have tried the "just jam the bullet" deal and I have tried the pistol powder deal with a wad of tissue. I just got better Dasher brass using the false shoulder/jam combo. I guess I am goofy and like doing that kind of stuff (creating false shoulders). I actually like FFing dasher brass. I have 500 FFed now and I never shoot a Dasher any more!!

Thanks,
Tod

 

[Scott Harris]

What you are seeing is normal. Brand new brass from lapua is around .008" short in my barrels which are chambered GO +.002. You are good to go.

 

[clowdis]

A "field" gauge has .008 clearance and you are about in that same area, so just load it and shoot it. Since this is a safe clearance set by SAAMI you should be fine. When you resize the shoulder you can set it to where you have around .002 setback.

 

[billlarson]

Why not just jam the bullets tight in the rifling?

+3

 

[fguffey]

I just got a new 6.5-284 bbl back from the smith. I ran 3 rounds through it for break-in with no issues

It would seem had you measured the cases length before firing and again after you would know the difference in length between the case from the shoulder to the case head and the chamber when measured from the shoulder of the chamber to the bolt face, The difference between the two lengths would give you the clearance.


Then there is always the gun smith that cut the chamber; why doesn’t he know the length of the chamber from the shoulder of the chamber to the bolt face. I was in a gun shop when a customer walked in and wanted his head space checked. The rifle was a magnificent example of craftsmanship. The owner/smith informed the owner of the rifle he did not have a head space gage for his chamber; the customer left.


After he left I informed the smith I could measure the length of any chamber from the shoulder to the bolt face without a head space gage. Normally that just locks smiths up, not this one. He asked me “HOW!?” I am not used to that but the smith is one of the few with a lot of class.


I showed him how then explained to him the disadvantage of using head space gages. I want to know the length of the chamber in thousandths. And then I explained to him I could modify his head space gages to measure from go to infinity.


F. Guffey

 

[fguffey]

He calls it .003 headspace...and I believe him without a doubt!!!!

When ever tool is a head space tool and every thing has head space I suppose a smith could say the case has head space and the chamber has head space the the difference between the two lengths is called head space. I do not agree, I would call the .003" difference in length clearence.

F. Guffey

 

[FatBoy]

My smith cuts my chambers so there is just the slightest drag on a go gauge with te firin pin removed. Needless to say, it's tight. I have some Lapua palma brass that has not been going off due to excessive HS. Not many, just four out of 80 so far, but enough. I was thinking the BR4S were bad but it looks like I just have some short cases.

To be honest, I just run my brass through a neck mandrel and load. No way I would be fire forming in a 6.5x284 unless I had an old barrel just for this.

 

[dedogs]

It would seem had you measured the cases length before firing and again after you would know the difference in length between the case from the shoulder to the case head and the chamber when measured from the shoulder of the chamber to the bolt face, The difference between the two lengths would give you the clearance.


Then there is always the gun smith that cut the chamber; why doesn’t he know the length of the chamber from the shoulder of the chamber to the bolt face. I was in a gun shop when a customer walked in and wanted his head space checked. The rifle was a magnificent example of craftsmanship. The owner/smith informed the owner of the rifle he did not have a head space gage for his chamber; the customer left.


After he left I informed the smith I could measure the length of any chamber from the shoulder to the bolt face without a head space gage. Normally that just locks smiths up, not this one. He asked me “HOW!?” I am not used to that but the smith is one of the few with a lot of class.


I showed him how then explained to him the disadvantage of using head space gages. I want to know the length of the chamber in thousandths. And then I explained to him I could modify his head space gages to measure from go to infinity.


F. Guffey

Wondering if you would care to elaborate on how you do this?

 

[M-61]

Quote from fguffy:
"I showed him how then explained to him the disadvantage of using head space gages."


And the disadvantages are????????

 

[dkhunt14]

He probably won't answer. I wish he would answer what the difference is between what he calls headspace. The difference between the bolt face and the shoulder. Then why a fired case at that measurement isn't headspace whether short or long. I mean Hornady, Sierra and most reloading manuals refer to it as headspace.
Matt

 

[M-61]

He probably won't answer. I wish he would answer what the difference is between what he calls headspace. The difference between the bolt face and the shoulder. Then why a fired case at that measurement isn't headspace whether short or long. I mean Hornady, Sierra and most reloading manuals refer to it as headspace.
Matt

You are right......I usually don't bother with his posts.

 

[fguffey]

And the disadvantages are????????

For everyone but me head space gages come in three lengths, go, no and beyond. I want to know the length of the chamber in thousandths. The OP had a rifle built; his smith can not tell him the length of the chamber in thousandths. Then there is that part about .003” head space, When I want to know how much head space a chamber has I measure the length of the chamber from the shoulder/datum to the bolt face.


I have a in-line, angle, butt grinder. It is the perfect tool for making head space gages. It just seems to be easier to make one that would take care of all the variables and tolerances etc..

F. Guffey

 

[fguffey]

That measurement could/would very from person to person, because there is no set point on the shoulder as a datum.
The gauge you grind with your in-line butt grinder will still be subjected to diameter and angle variances to where at on the shoulder it will make contact, there for so will be the length measurements.

How can that be? I have no ideal how someone could talk themselves into believing it can not be done. I have standards for checking micrometers. , if I do not have one I make it. Then there is verifying, I have head space gages, there are no variables.


Same for shell holders, the deck hiehgt of my shell holders is .125”, if one of my shell holders does not have a deck height of .125” I know it; because I measure the deck height of my shell holders. I have a set of Redding competition shell holders for belted cases, I paid $5.00 for the set. Why so cheap, I do not know, it is possible someone measured the deck height and found three of the shell holders were off by .001” each. I could purchases another set, the other set would give me 10 shell holders with 8 different deck heights. Meaning? I would only be missing 2 of the 10.

 

[Shaggy357]

Brass fired in a specific chamber and still has .007" excessive head space has already stretched some, and may stretch more, depending how you size it. Neck sizing alone, with no "anti-stretching" measures leaves .007" of uncontrolled space for the brass to expand. History and experience has shown many of us that this stetching usually occurs in area of least resistance in the chamber which is just shy of where the die stops above the shell holder. It may take 3 or 4 firings, but repeat stretching in this area can lead to case head separation.

Go, no-go, and field gages are there for one reason; to help the gun builder ensure his finish cuts in the chamber are getting close to meeting the specifications of the gage he wants. Most builders stay within SAAMI specifications as that is what most commercially available ammunition is manufactured to. Do NOT use gage measurements or books to tailor your handloaded ammunition. These are reference points from which to start.

Cutting reamers wear as they are used. Most cutting is by hand, by feel, and as such the chambers are close, but not exactly the same. Consider the reamer used by the smith, made by manufacturer A, to certain specs, is cutting your chamber, which could be first, second, or thirtieth cutting. Die manufacturer X is using a reamer made by manufacturer B, to make dies to form all brands of brass, to size within SAAMI spec, and, due to cost and demand, your die set could be first, third, or fiftieth set made. Then the dies are heat treated.

New dies, chamber, brass, etc. That is a lot of variability you are gambling on to ensure the ammo you create fits your gun perfectly. YOU have to minimize how that variability effects your ammo in your gun.

The brass that fits your chamber perfectly can only be created in your chamber. Bullets seated out to engage rifling, false shoulders, Cream of Wheat, and other methods are used, or used in combination, to make these "fireform" loads fit your chamber. You then have to set your dies, using YOUR chamber as a guide, to size the brass to fit the chamber, leaving a controlled amount of room for expansion and relaxation.

Took a lot of words to reach the point. If you are going to spend the money on the expensive gun, the high value dies, and the $2 or $3 per each brass, take advantage of the opportunity by spending the time and techniques to make ammo worthy of firing in the gun.

 

[4xforfun]

Well..I finally took 45 min out of my life. I ran a .277 "E" mandrel through the 100 pieces of brass, ran them again about 80% into my body die, and finished them off with a .295 bushing in my neck die to get a FIRM crush fit.


It will be -20F this weekend, so load development will be a no-go, and then I will be spending some time in Idaho riding snowmobile with my Kids. I'll get back to shooting eventually!!!

Thanks Again,

Tod

 

[Dusty Stevens]

I cant think of a gunsmith out there that chambers a barrel without headspace gages. Even if its not a saami cartridge the reamer maker makes a gage for that reamer. Everybody that chambers a barrel knows if their chamber came out at zero or +.003 and they all understand that. Wtf does oddball shell holders and their deck height have to do with any of this? Fireform brass in that exact chamber. If you dont youre just on your own