6.5X55 headspace

[TikkaBob]

I have done some reloading for a .223 Tikka T3 and want to start reloading for my Tikka T3 in 6.5x55. According to the SAAMI site, the case head to datum line (headspace) measurement is 1.712 (although Sierra and Nosler cite 1.704). I measured headspace of unfired and cases from fired PPU-loaded ammo using a Hornady headspace gauge, and new, unfired Lapua brass and got readings in the range of 1.7605 to 1.7660. I ran fired and new cases thru an RCBS FL sizer set to lightly cam over, and the headspace measurements were more or less the same for the fired cases and the new Lapua brass. According to SAAMI, the min and max chamber headspace values are 1.7834 and 1.7934, so the fired brass is still 20 thou or so short of minimum, and that seems strange to me and potentially dangerous- but I am new to this. The commercially loaded PPU shot fine in my rifle but I am concerned about what seems to me to be a potential headspace problem being 20 thou or so short. So, worry about it or not? Suggested path forward? Am I missing something?

Thanks for your advice.

 

[243winxb]

Hornady headspace gauge,

Its not a headspace gauge.

It is to compare fired brass to sized brass. Sized brass should be about .003" shorter/less head to datum then the fired brass.

Fired brass may not fully expand to the chamber, giving a false measurement.

Start fl sizing with a .005" gap between shell holder and die. See if brass will chamber. Make adjustment from there.

 

[FatOldMIHunter]

I have just been through this with my new 6.5 Swede and both new and used cases. Using the Hornady headspace comparator, I discovered that my rifle will not chamber any cases larger than 1.766". That is the crucial number regardless of SAAMI spec (for my rifle). My RCBS FL sizing die will get me down to 1.764", provided the brass is soft enough to not resist sizing. New Hornady brass came in right at 1.763+- .001, but fell .015 below the case length minimum spec of 2.145". I ordered some Lapua brass today.

 

[TikkaBob]

243winxb, thanks for the advice. I guess my question boils down to this: is Hornady incorrect to call their gizmo a headspace gauge? The measurement from head to datum line using the gauge is not the same as shown in the SAAMI or relaoding manual measured drawings, and the measurement of cases fired in my rifle fall significantly short (~20 thousands) of the minimum SAMI chamber spec. I had expected that head to datum measurements of fired cases would be somewhere between the SAAMI min and max chamber values, IF the Hornady bushing was measuring headspace as defined by SAAMI and others.

 

[243winxb]

This is a headspace gauge. https://www.midwayusa.com/product/562043/forster-headspace-gauge-field-length

 

[Laurie]

In answer to your question, it is incorrect for Hornady to call it a 'headspace gauge'. It is a case-comparator doing the same job as the bushings sold as bullet comparators (as used for bullet BTO measuring and batching / identifying and setting COALs). In this form it does exactly the same job but provides data on case shoulder position rather than that of bullet ogives.

 

[FatOldMIHunter]

Hornady calls it
Lock-N-Load® Headspace Comparator & Anvil Base Kit

They specifically do not call it a headspace guage because that would be a representation of a cartridge case minus the neck. It doesn't guage the distance from the bolt face to the chamber shoulder datum line. That would require a huge set of guages and the goal would be to find which guages chambered when they should or when they shouldn't and which didn't chamber when they should. That's why they use a go and nogo specific to each caliber.

The Hornady headspace comparator measures from the cartridge case head to a case shoulder datum line. If you have enough cases of varying lengths, you can discern the headspace of your rifle by finding one that chambers tightly and verifying that it is the shoulder that caused that. If you look in the Reloading forum, you will find two threads where I went through my issues with a new Swede rifle's headspace. One is titled "Resizing Failure" and the other is titled "Short necked brass. Is this to be expected?"

 

[243winxb]

Soon, someone will come along and say cartridges don't have "headspace".

http://www.saami.org/specifications_and_information/index.cfm

 

[Ringostar]

If you look at your comparator, the point of contact with the shoulder doesn't have a sharp edge. It has a bevel that lets the shoulder sit in a little deeper. That will give you slightly shorter measurements. The shoulder contact point will change with various shoulder angles also. Think of the angle of a 30.06 vs a 40 degree Ackley. Measure a once fired pic of brass, if it still chambers fine then don't set the shoulder back from there. Load and fire that case again, then take another measurement. It might be longer then the first time you measured it. Once again check if it chambers freely. When you get it to the point of snug rechambering, then you can get an actual measurement of your chamber. Also the hole and bevel of the Hornady comparators can vary from one to another. Mine might measure the same case different than yours. Also calipers can read differently.

 

[KMart]

Trying to figure out the specs on a 6.5x55 can give you heartburn.

It can be a 6.5x55 built to SAAMI specs.

It can be a 6.5x55 Swede built to CIP specs...European standards

It can be a 6.5x55 Skan built to CIP specs

The Tikka, I assume, is built in Europe and I would think that is built to one of the CIP standards.
All 3 possibilities have different specs.

 

[TikkaBob]

Thanks to all of you who replied; a fine example of truth versus marketing. I will no longer worry about my "erroneous" data.

Kmart- as you noted, the Tikkas are made in Europe and meet CIP criteria. Regarding different specs, the 6.5x55 seems to be a classic case of different specs. But, mine seems to really like the PPU 120 gr BTHP match ammo: 3 touching at 100 yards, consistently. My wallet, on the other hand, does not like factory ammo for this caliber.

 

[243winxb]

Trying to figure out the specs on a 6.5x55 can give you heartburn.

I know more than i want to and i dont own one.

More info i posted here.
http://forum.accurateshooter.com/threads/differences.3942788/

http://www.shootingtimes.com/ammo/hunting-ammo/a-metric-marvel-6-5x55-swedish-mauser/#ixzz54E00dwLm
Added drawing and measurements of both athttp://stevespages.com/page8d.htm

 

[Flouncer]

Does your Tikka evidence any difference in chambering Made in USA vs Made in Europe factory ammuntion ? The case DIAMETER for 6.5x55 is non-standard, i.e. bigger than typical 7x57 or .308 size. I thought USA ammo was made to the local normal .308 case diameter. I always wondered about the Lapua, Norma and Privi ammo. - thanks I have a Gustafs Stads and fired Winchester and Federal cases show a light faint ring a little way up from the case base.

 

[TikkaBob]

I know more than i want to and i dont own one.

A friend sent me the Shooting Times article, and it pushed me over the edge of resistance and I bought one. I don't regret buying it, but it certainly isn't as straightforward as loading for my .223 bolt action. Thanks to the input from forum members, I am going to start load development for it.

 

[TikkaBob]

Does your Tikka evidence any difference in chambering Made in USA vs Made in Europe factory ammuntion ?

I've only tried the PPU factory loads, not sure about those made here. I have read posts about trying to fire-form .308 cartridges into 6.5x55 SE and the potential problems of the different case head size.

 

[SBS]

Does your Tikka evidence any difference in chambering Made in USA vs Made in Europe factory ammuntion ? The case DIAMETER for 6.5x55 is non-standard, i.e. bigger than typical 7x57 or .308 size. I thought USA ammo was made to the local normal .308 case diameter. I always wondered about the Lapua, Norma and Privi ammo. - thanks I have a Gustafs Stads and fired Winchester and Federal cases show a light faint ring a little way up from the case base.

The light ring ahead of the solid case head is normal on fired ammo, as new brass is nearly always smaller than the chamber and the thinner brass swells out to chamber size (if the head swelled out to this size, you'd be running some ferocious pressure). U.S. made brass for the 6.5x55 is not the same diameter at the rear as .308, 7x57, and similar cases. Reloading manuals caution you not to make your Swede brass from such cases. The diameter just ahead of the extractor groove on .308 is .467-.468. while the Swede is .472 or larger. Unfired Rem. brass I have measures .472 for rim size and .474 just ahead of extractor groove. New Win. is .473 rim size and .472 ahead of EG. In contrast, Lapua has a .478 rim dia. and .477 just ahead of EG. I speculate that Rem. and Win. rims are smaller to try to accomodate U.S. made rifles with enclosed bolt faces. I looked into this when I wanted to make a custom 6.5x55 target rifle and found out Lapua brass would not fit into the bolt face of a Rem. or push feed Win. 70 I had. Wasn't too much work to open up the Win., but the Rem. 700 would have required an extractor job after opening up.
When I had a 96 Swede, I fired Norma, Win. and Rem. brass thru it, reloaded them several times each and had no problem with the brass. However, it does make one decide on a brand of brass first in order to secure the proper reamer for best accuracy and long brass life.

 

[KAIFS]

Most of my shooting/reloading/collecting is 6.5x55. I have a fair number of rigs in this caliber both commercial and military (swede mauser(s), ljungman(s), Norwegian Krag(s)). this is what I can tell you for sure, based on thousands of rounds of shooting/reloading - USA made brass for 6.5x55 is junk. do not get me wrong, I love my Country, it just swede brass we can't get right... My brass choices are, in this order: LAPUA, NORMA, NOSLER; everything else is NOT consistent, sized wrong, and has lower number of reloads (even with slow 2400-2600fps velocities).
As far as rim dia - I have several custom modern rifles, which were reworked from 30-06 and 270 into 6.5x55 and I have 0 problems with original .473 bolt faces. I did, however, ran into few issues with early/older Norma brass which was, indeed, in .480 range for the rim. 6.5x55 factory: R700, Browning X-bolt, Win 70, Ruger M77 all have a standard .473 bolt face and not a glitch with modern Lapua or Norma brass...