A problem with blanks; my story.

[jjprzewozniak]

Hi everyone,

I'm in dire need of some expert advice here. This place is an absolute treasury of knowledge, and I appreciate the expert guidance anyone can receive here, especially from Blanksguy, whom I hope can help out here!

I own a TNW SA34 that fires live ammo great. I will tell you of my experience blank-adapting it, and the resulting problems I now need advice on.

For starters, the blanks I use are the "full length" ones made by Atlantic Wall (http://www.atlanticwallblanks.com/8mm_blanks.html). The total overall length is 70.71mm. I also have the shorter ones from the same maker, that measure 65.93mm overall.

My blank adapter is the Guiette Mfg. 1-Pcs. Blank-Adaptor.

The first time: With my guiette adapter installed and no other modifications on the MG, the only problem I had when using the long blanks was the familiar jam that occurs when the blank rides up and strikes the top of the "tunnel" instead of feeding down properly. This is a familiar problem, and I learned about the remedy from Blanksguy. I purchased the MG34 feed tray spacer from him.

Realizing that it needed to be altered to allow any blanks to fit, I was faced with a dilemma. My long blanks would require much grinding to allow them to fit, so I proceeded to shape my new feed tray spacer to accommodate the shorter blanks. The attached photos will show what I've done--sorry for the photo quality. After a little dremel work, the short blanks seemed to glide nicely in place when the spacer is attached to my tray.

The second time: With Guiette adapter installed and feed tray spacer in, the MG34 turned the short blanks into pretzels, but only when it refused to eject the spent casing from the barrel, all the while NOT fully cycling. Yep, I was frustrated, but intrigued too. NOTE: BFA was set to the smallest opening possible: .154. To be clear, here's what happened every time I attempted to fire:

SCENARIO 1:
blank feeds, fires, does not eject, does not cycle, requires poking the spent case out of the barrel with a stick.

SCENARIO 2:
blank has difficulty feeding, I manually override the mechanism by forcing the bolt forward, the unfired blank gets severely bent requiring manual retrieval.

To me, it seems that the short blanks are the source of the problem. I intend to revert back to using the long blanks, which would require much more grinding on the feed tray spacer. I am timid of this because I fear I may grind off an essential component of the feed-tray spacer. (I have only an amateur's familiarity with things mechanical, etc., and my lack of expertise of the science behind the feed tray spacer makes me very cautious) My idea is to, quite simply, grind off everything that is in the way of the longer blank. Is this the right thing to do?

Please, if anyone has any advice to give, I need it! I am under pressure to present a WWII firearms demo for a museum project, and I must fix this problem very soon. Blanksguy, your feedback here would be invaluable, as would any who can offer expert insight to this problem.

Thank you so much.

Most respectfully submitted,
JJ Przewozniak





The second time

[jjprzewozniak]

Just for further clarification, here's some more photos that show what I've done to the feed tray spacer, and what I would need to do in order to accommodate the longer blanks. The red indicates areas that would be eliminated to fit the longer blanks.

Best,
JJ

[Blanksguy]

JJ,
......."Yep".......
This sounds like an "addition" to the end of the "Blank Adapting the MG34/SA34" thread down in the MG34 Section.

Let me know when you get it down there so I can post some additional information.
When you do post the question down there.....be specific about other bits of information such as/but not limited to:
1: We all know that these guns have to fire live ammo first.......before we start to Blank-Adapt then........how many rounds did you fire at the range (live ammo), and how did the gun operate (?).
2: When the Blank was bent up......was there a cartirdge-case that was not ejected still in the chamber or ejection-port area (?).
3: When you talk about Blank and Blank-Adapting......are you using an 8x57mm barrel or .308 barrel (?).......
4: Are you using 8x57mm Belts or the 7.62x51mm/.308 cal. Belts (?).
5: Did you read all of the "Blank Adapting the MG34/SA34 Thread" (?).
6: Have you considered the purchase of a 2-pcs. Blank-Barrel-Assembly in either 8x57mm or 7.62x51mm/.308-cal. (?).....these require less pressure to operate as the only part/weight of the barrel that is required to move is the lighter piston/rear-section.......this equates to allowing more reserve pressure = bigger BFA Hole-Size at the muzzle and/or more positive operation of the bolt-assembly.

On the "L"-shapped Feed-Tray-Spacer........you can grind it to allow the longest Blank that you will be using "and" it will operate with the shorter Blanks..........but note: if you have any "dragging" or binding.....you need to recheck clearances and make adjustments to the spacer so that the Blanks will slide into the spacer, and then allow them to drop out the front......no "dragging"/binding allowed.

Regards, RichardS in MI.
US Army, Retired.
Blanksguy2001@chartermi.net