7.92 chamber depth

[Peter Laidler]

It doesn't work like that Vince......... Think about it while you have a BLN in your hand! I don't think the one Wally mentioned was done like this for the same reason

[TactAdv]

As far as I am aware these 8mm conversions went into guns with out any modification to the gun and I never received a complaint about not fitting or functioning.

What did people use for magazines to feed the 8mm ammo.....those who got your sets??

I know of no other magazine that will hold and properly feed 8mm ammo except for the std CZ Vz.26/30 mags?? I have one of those barrels too. My problem is my original Daimler Mk II .303 receiver will need to be slightly relief cut at the very back of the mag well to allow the Vz26/30 mags to fit down into the rear of the well, and then lock into place.

Even more problematical, is that there are well known differences in 7.92x57MM JS ammo produced "to military acceptance standards" up to 1945, and after. The older made ammo is markedly shorter in cartridge OAL specs, enough that trying to stuff more modern manufactured 8mm ammo, say the Romanian 8mm for this discussion, into a WWII or earlier made CZ Vz. 26/30 or Inglis made 8mm magazine doesn't necessarily work...at all.

This situation is the norm for all std .303 receivers, I believe. So, unless you are starting with an original 8mm receiver, or can make the needed accommodations when you put back together a cut receiver, I am not sure how you feed the gun 8mm ammo?

-TomH

[Joe H]

Even more problematical, is that there are well known differences in 7.92x57MM JS ammo produced "to military acceptance standards" up to 1945, and after. The older made ammo is markedly shorter in cartridge OAL specs, enough that trying to stuff more modern manufactured 8mm ammo, say the Romanian 8mm for this discussion, into a WWII or earlier made CZ Vz. 26/30 or Inglis made 8mm magazine doesn't necessarily work...at all.

This situation is the norm for all std .303 receivers, I believe. So, unless you are starting with an original 8mm receiver, or can make the needed accommodations when you put back together a cut receiver, I am not sure how you feed the gun 8mm ammo?
-TomH

Tom,

I finally got my 7.92 out to the range Sat. Barrel is a .303 rebored & rechmbered .303 and the gun is a MKII. Unfortunately I only took one 8mm mag with me, the one that I didn't realize won't lock up properly. All the others do and I have since repaired the offending mag. Bottom line is that I couldn't test the mag live fire.

I have one zb-30 mag and a number of the Spanish mags. Numrich sells. The Spanish knocked off the zb30 and made mags for it.

Magazine Set w/ Leather Shoulder Strap Gun Parts | 1369890 | Numrich Gun Parts

Both types of mags seem to work with my 8mm ammo. They don't jam hand cycling and strip easily by hand. I think the problem is the OAL of the cartridge. Attached below find the current CIP. Note that OAL is 82mm. All prewar 8mm was 80.5. I don't have any Romanian.

I have some Yugo 1956 surplus OAL 80.16mm and some new PPU 8mm mauser 80.5mm. The PPU just fits. In making up dummies for trial cycling I quickly found out that a less extra (over 80.5) would cause jams. I don't think the problem has anything to do with the receiver, just the inside length of the mag. 82 mm just doesn't appear to fit.

Joe

[WallyG.]

Tom:

I have a .303 receiver that has been relieved for the ZB26 mags... I've not tried very many ammo variations... and have not yet run into the reported feeding/mag issues... but I'm sure I will. The other gun is a true 8mm receiver (Inglis made resistance gun) so it probably was less work to fit up with the Zb26 mags. I have a supply of both Czech and Spanish made mags... and have yet to notice any functional difference. I did manage to scrounge one Canadian 8mm mag... you'd think that they'd be easy to locate here in the states... but such has not been my luck.

ATB

Wally G.

[ActionYobbo]

What did people use for magazines to feed the 8mm ammo.....those who got your sets??

-TomH

whats wrong with the 7.92 bren gun magazines.

[TactAdv]

whats wrong with the 7.92 bren gun magazines.

Nothing, if your receiver will accept them!! ;-)

As I, and now others, have noted, the original .303 receivers are just shy at the back wall of the magazine well to allow the standard vz.26/30, FAO, or Inglis mags to drop all the way down and latch.

I think some people are missing the fact that my statement was in relation to only all-original guns like my Daimler Mk II, i.e., un-cut and welded back. My receiver is exactly as it came off the line when it was made. I suspect that those individuals who can get the vz26/30-FAO-Inglis mags to fit are using a receiver that has been cut and put back together.......such a process might allow the needed slack to be introduced. It really is a VERY small amount that the back wall needs to be relieved...and this "slack" could easily be introduced in putting one back together.

A factory original .303 receiver is marginally shorter than a factory 8mm Inglis receiver. Since the Canadians chose to merely copy the existing and proven CZ vz.26/30 mag it is almost certain they too discovered and adapted this necessary change to the mag well dimensions.

Also as I said, my concern is mostly to do with finding a suitable magazine to use that will fit the more modern 8mm dimensions. All these mags were originally designed around specifications for 7.92x57JS ammo that was markedly shorter in cartridge OAL.

So there are in actuality TWO fit issues- One, does the selected magazine fit into your receiver, and SECONDLY, does the selected magazine accommodate and properly feed the variety of 8mm ammo you intended on using.

In my factory original guns' case, 8mm mags do NOT just drop in and latch (as expected), and the CZ vz26/30 mags I have tried do not accommodate the Romanian 8mm ammo I was hoping to use.

I have not yet tried loading the Romanian ammo into ZB-39 mags I have- I would be pleasantly surprised to discover that it would work as the ZB-39 mags fit perfectly into my receiver and are in fact, what I use to feed .308/7.62mm NATO ammo.

-TomH

[Joe H]

I think some people are missing the fact that my statement was in relation to only all-original guns like my Daimler Mk II, i.e., un-cut and welded back. My receiver is exactly as it came off the line when it was made. I suspect that those individuals who can get the vz26/30-FAO-Inglis mags to fit are using a receiver that has been cut and put back together.......such a process might allow the needed slack to be introduced. It really is a VERY small amount that the back wall needs to be relieved...and this "slack" could easily be introduced in putting one back together.

So there are in actuality TWO fit issues- One, does the selected magazine fit into your receiver, and SECONDLY, does the selected magazine accommodate and properly feed the variety of 8mm ammo you intended on using.

In my factory original guns' case, 8mm mags do NOT just drop in and latch (as expected), and the CZ vz26/30 mags I have tried do not accommodate the Romanian 8mm ammo I was hoping to use.

Tom,

Give it a try but I think I tried 8mm mauser in the ZB39 mag and the mag was too small. The 8mm is between 4.5 & 6mm longer than the 8x56r.

I'm using the zb30 mags in a semi weld up. I had to grind material from the lower rear of the mag well for it to fit. It was not an insignificant amount with an air pencil grinder. After the grinding it still accepted .303 & zb39 mags. IMO if a std .303 Bren weld up accepted the ZB-30 without the mag well mod then you would be very susceptible to loose fits with both ZB39 & .303 mags. and maybe problems with headspace.

For using the Zb39 mag for 7.62x51 I found that I had to remove the box guide under the follower and grind off about .032" from the horns of the mag follower or the last round would jam or not feed. Once you get your 8mm zb30 mag to fit it will also feed 7.62x51.



Joe