Headspace Gauges

Drachenblut

Drachenblut

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Hello,

I am looking for where I can purchase headspace gauges for the milsurp .303 British and 7.62x54R cartridges, both a go and no-go guage are required in both instances.

I live in South Western Ontario. If anyone knows of gunsupplys that offer these or have some they would like to part with, contact me via PM or here on this thread.

Thanks,
Drachenblut
 
Drachenblut said:
Hello,

I am looking for where I can purchase headspace gauges for the milsurp .303 British and 7.62x54R cartridges, both a go and no-go guage are required in both instances.

I live in South Western Ontario. If anyone knows of gunsupplys that offer these or have some they would like to part with, contact me via PM or here on this thread.

Thanks,
Drachenblut
Click to expand...


Member Gairlochian sells repro military .303 headspace gauges for a reasonable fee. As for the Russian cartridge, maybe Brownells?
 
On this note, where can I buy Lee Enfield no.4/no.5 boltheads? I have a number 1 on my rifle now and after reloading, noticed stressing in the cases... perhaps it's time to move up to a number 2?
 
Well - If I recall, the Russian cartridge is rimmed. Perhaps the 303 is adaptable in some way, if not, perhaps Garlochian could make some up..
BTW - Partially resizing your cases will give better results than swapping boltheads...
 
Me and a friend made some for .303 on his lathe.

as for case stressing, I always notice slight stressing, even with correct head space. I think the tapered case on the .303 makes it more obvious.
 
"...noticed stressing in the cases..." Check the headspace first. Brownell's carries 'em. So do most of the reamer rental/sale shops Stateside. Try Epp's too.
You can buy 'em direct from Clymer or Forster as well. They may or may not ship to Canada.
"...Perhaps the 303 is adaptable..." Nope.
 
I have a .064, .067 and a .074 .303 British head space gauges, if you have a set of vernier calipers you can be a cheap bastard and do without head space gauges. All you need is a spent fired primer, a new unfired case or a full length resized case (rimmed) and your vernier calipers.

Using this method you will be measuring your head gap clearance or the “air gap” between the rear of the case and the bolt face. The “air gap” is what causes case head separations and the “air gap” is how far your cases will stretch in the web area.

headspacestretch_frame_000.jpg


1.First measure the overall length of your new unfired case and write it down.
2.Next seat the fired primer in the primer pocket and close the bolt.

NOTE: Chambering and fully closing the bolt pushes the primer in but the primer will be sticking up at the rear of the case equal to the head gap clearance or the “air gap” between the rear of the case and the bolt face.

3.Re-measure your case again and write it down
4.Now subtract your first case measurement from your second case measurement and you will have your head gap clearance or air gap measurement.
5.Now measure you rim thickness and add this to your head gap figure and you have your exact head space.

Example:
2.231 – 2.222 = .009 (nine thousandths) head gap clearance or air gap measurement.
Rim thickness measurement .059
.059 + .009 = .068 actual head space measurement.

What does this mean to you? That depends if you reload or not or if you toss your once fired brass. The stretching in the web area is what is what causes your brass to fail early.

headspacestretch-1.gif


Below is a factory loaded Winchester case fired in my 1943 Maltby, the Enfield's head space is .067 and my rim thickness is .058.

.067 - .058 = .009 nine thousandths head gap clearance or “air space”.

The Winchester case below stretched and thinned .009 in the web area when fired.

IMGP4523.jpg


IMGP4521.jpg


IMGP4513.jpg


If you reload you can “cheat” head space by slipping a rubber o-ring around your case and fire form it with “ZERO” head space. You neck size your case and it will be head spacing on the shoulder and not the rim at the next firing.

With the o-ring around the rim of the case when chambered the case if forced against the bolt face eliminating the head gap clearance or “air gap” and the case can not stretch and thin in the web area.

IMGP5098.jpg


IMGP5096.jpg


Reloaded three times “WITH OUT” fire forming using the rubber o-ring

IMGP5191.jpg


Animated .gif images from Parashooters “Head space 101”
 
Big Ed...that is one of the most informed, informative headspace writeups I've ever seen! My hat's off to ya!

Good stuff.

The o-ring trick is a winner for reloaders!

The only issue I have with fireforming cases to a specific rifle is they probably won't chamber in the next rifle you try them in...thus having to segregate brass for each rifle.

Every Enfield seems to have a chamber of varying depth...My 1950 Long Branch was tight enough that the brass shoulder barely expanded...an old SMLE on the other hand might see the shoulder move forward considerably.

But that o-ring trick is clearly the route to having brass that lasts.
 
make sure you get one that is military specs, not sammi specs.

i bought a sammi spec gauge and the bolt closed when it shouldnt have. i read up further and a lot of people told me that the enfield is built for loose tolerances.

the gun fired fine.
 
Mhmm. I'll make sure. That headspace trick is great... so basically I do not have to full length re-size? I do not have vernier calipers (nore do I know what they are). That o-ring thing works well eh... question, can I do that with full length resizing anyways?
 
DiSmAnTLeR said:
make sure you get one that is military specs, not sammi specs.

i bought a sammi spec gauge and the bolt closed when it shouldnt have. i read up further and a lot of people told me that the enfield is built for loose tolerances.

the gun fired fine.
Click to expand...

I have both Field gauges, SAAMI and military. A rifle that passes to SAAMI spec has tighter headspace...that's not a bad thing.

As long as you don't reject a rifle because it failed SAAMI...if it does, you just insert your .074" military Field gauge next and if it passes then it's fine. Both gauges have their use.
 
Drachenblut said:
Mhmm. I'll make sure. That headspace trick is great... so basically I do not have to full length re-size? I do not have vernier calipers (nore do I know what they are). That o-ring thing works well eh... question, can I do that with full length resizing anyways?
Click to expand...

Very few people full length resize with .303. Plan to use Lee Collet dies and neck size only. Adding the o-ring trick to that equals max case life.
 
cantom said:
Big Ed...that is one of the most informed, informative headspace writeups I've ever seen! My hat's off to ya!

Good stuff.

The o-ring trick is a winner for reloaders!

The only issue I have with fireforming cases to a specific rifle is they probably won't chamber in the next rifle you try them in...thus having to segregate brass for each rifle.

Every Enfield seems to have a chamber of varying depth...My 1950 Long Branch was tight enough that the brass shoulder barely expanded...an old SMLE on the other hand might see the shoulder move forward considerably.

But that o-ring trick is clearly the route to having brass that lasts.
Click to expand...

Cantom

In the old Jouster forum a smart Canadian posted the o-ring trick about 3 or 4 years ago, I'm just passing it on and can not take credit for the fantastic idea.

The o-ring as it is compressed on bolt closing “centers” the case in the chamber promoting equal case expansion in the base web area.

I was (past tense) always in favor of tight head space on the Enfield because of the British maximum head space of .074 and because our American made cases were designed for less head space. Meaning our commercial brass is made thinner than military grade brass and not really designed for long fat chambers.

I lapped a #0 (zero) bolt head and took my head space to .084 and fire formed cases with the o-ring with NO ill effects. (no case stretching or thinning)

A few years back at the Gunboards forum someone went to a lot of trouble to make a much longer bolt head to eliminate excess head space-head gap clearance. The rubber o-ring eliminates the need for longer bolt heads within reason and saves your brass.

I also recommend using Prvi Partizan .303 cases, they are over .010 thicker in the base web area and I consider them “military grade” because of being thicker and being larger in diameter in the base web area than American SAAMI cases.

Below, once fired Prvi Partizan case on the left and Greek HXP case on the right.
(fired without the o-ring)

privihxp.jpg


Without the rubber o-ring I was only getting 3 or 4 reloads from my Winchester brass and I was neck sizing the cases.

IMGP0737.jpg


The only downside to the rubber o-ring are thin cases with small base diameters with a rifle with a fat or large diameter chamber. These cases will expand more on one side and warp and become “banana” shaped and destroy bullet alignment with the bore.

Please notice the red arrows and the “angled” case split above, this case expanded more on one side and caused the uneven “angled” case split. Again this is a commercial SAAMI small base diameter case fired in a large diameter military chamber so you blame the brass case and NOT the Military Enfield rifle.
 
Drachenblut said:
That o-ring thing works well eh... question, can I do that with full length resizing anyways?
Click to expand...

NO

Full length re-sizing defeats the purpose behind the rubber o-ring, you want the case to head space on the shoulder of the case and NOT the rim, and always be touching or in contact with the bolt face. You use the o-ring once or twice depending on how “hot” or how much pressure the case was loaded too, and then the o-ring is no longer needed.

During WWI the chambers of the military Enfield rifles were enlarged to make room for the “mud of Flanders” and our American SAAMI reloading/resizing dies have NOT been enlarged. Every time you full length resize the .303 case you are pushing the shoulder of the case back at least 1/8 to a 1/4 of an inch.

Again look at Parashooters image from head “space 101” I have added the rubber o-ring indicated by the red arrows, now look at the front of the chamber and the poor fit of our commercial case in the military chamber. Fire forming the case blows out the shoulder of the case and brings it into contact with the shoulder of the chamber, from this point onward the shoulder of the case is holding the rear of the case against the bolt face. (zero head space and NO case stretching)

headspacestretch_frame_0001.jpg
 
A little note to ponder about head space.

A bottle neck case like the commercial .308 Winchester is made with the shoulder of the case .002 shorter than minimum head space to ensure it fits a minimum size chamber. To measure head space using a new unfired case you would “subtract: .002 to get your head space reading.

In the photo below I'm checking head space on my Ishapore 2A1 7.62 (.308) Enfield, I have a new unfired case in the chamber and a feeler gauge inserted between the right locking lug and the receiver.

A .010 feeler gauge fits between the right locking lug and the receiver, I subtract .002 and my head gap clearance is actually .008. The 2A1 head space is just at the field head space setting for a M-14 rifle and is “close enough” to safely shoot .308 or 7.62 NATO ammunition.

2A1b.jpg


I do not have .308/7.62 head space gauges, but I do have a RCBS Precision Mic, with this I can measure a unfired case and a fired case and find out my actual head space.

IMGP5130-1.jpg


Actual head space gauges are nice to have BUT they are like taking a test in school and then only finding out if you “passed” or “failed”, and sometimes you want to know your exact numerical score.

And sometimes the word “head space” means absolutely nothing. :eek:

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enefgee said:
Anyone know where modern military 303 fits in the continuum - I have some IVI 303, is it SAAMI or military dimensioned??
Click to expand...

Your IVI cases are military BUT they are thinner/lighter than commercial Remington cases.

CASE VOLUME - Water Weight in Grains

303 British

58.8 gr Remington (commercial)
56.0 gr IVI (military)
-2.8 gr or 4.8% difference

http://www.303british.com/id39.html
 
Not really all that surprising, given that it's an only bidder situation - at least it's boxer primed :D I wish the RG stuff I have was (and the FN and, and, and....) Looks like I'll have to invest in some Privi though. The rifles are worth it, one's unfired, the other has a new barrel fitted.
 
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