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View Full Version : bolt hold open ( BHO ) breakage


W.E.G.
September 16, 2001, 17:00
I haven't heard of this happening.

http://www.clark.net/pub/warwick1/BHO-crack1.jpg
http://www.clark.net/pub/warwick1/BHO-crack2.jpg
http://www.clark.net/pub/warwick1/BHO-crack3.jpg

The pics are pretty crappy. But who can afford a good digital camera when TAPCO and others are tapping me dry.

I was firing offhand, single-feed, when the BHO shaft just snapped at the mid-point where the hold-open pin is set in the shaft. I fired a shot. The rifle functioned normally. The bolt locked-back after the shot. I inserted another round in the chamber, and tried to close the bolt by pulling downward on the BHO. The BHO seemed to move. But, the bolt did not close. Inspection revealed that the short broken part of the shaft was still holding the bolt back as the rest of the BHO moved through its normal range. Removal of the top cover was necessary to remove the short broken portion from the BHO channel.

The rifle would still fire just fine after the short broken part was removed from the rifle. However, the bolt hold-open function was obviously eliminated in every respect by this failure.

I don't suppose this is any big deal other than that in my short experience with FAL's, I've never heard of it happening.

This particular specimen came from a Chilean IMBEL kit.

One thing that is especially interesting is the configuration of the BHO pin, that is the pin that the mag follower engages. The shape of the pin is more unusual than I would have expected. If you look at the drawing below, you can see that one end of the shaft is larger than the other end. The more narrow end appeared to be slightly swaged right at the external end of the pin.

http://www.clark.net/pub/warwick1/BHO-crack4.jpg

Timber Wolf
September 16, 2001, 17:49
Must have been really brittle, you would not think there is that much force. But hey, these are old parts. Was it on a Hesse receiver? If you can't blame it on anything else hang it on Hesse! :D

W.E.G.
September 16, 2001, 18:05
The failure occured on a Chilean IMBEL kit on a metric post-ban IMBEL.

My drawing is not quite to scale. Once the hole is drilled for the pin, there is considerably less "meat" left on the shaft around the pin than there appears to be in my drawing. The second and third blurry pics give you a pretty good idea of the relative sizes.

stimpsonjcat
September 17, 2001, 11:16
Yeah, looks like th pin is to blame here Gary.

Was this as issued or a modified piece?

W.E.G.
September 17, 2001, 13:25
Looks to me like "as-issued."

Radio
September 17, 2001, 23:13
I might use this opportunity to pile on here and comment on the surprising, disappointing quality of manufacturing displayed by these Chilean IMBEL kits that make my South Africans look positively sophisticated, but I wouldn't say that and I didn't and you can't prove I did and there's no evidence to suggest I might. :D

I go with the brittle theory. Just an oddity that slipped past QC. Think of it like that 1980 Larry Graham song, "One In A Million You."

--Radio

Newbie2FALs
September 19, 2001, 09:13
Originally posted by Radio:
<STRONG>I might use this opportunity to pile on here and comment on the surprising, disappointing quality of manufacturing displayed by these Chilean IMBEL kits that make my South Africans look positively sophisticated, but I wouldn't say that and I didn't and you can't prove I did and there's no evidence to suggest I might. :D

I go with the brittle theory. Just an oddity that slipped past QC. Think of it like that 1980 Larry Graham song, "One In A Million You."

--Radio</STRONG>

Radio, I know you didn't say that but if you had ;you'd be right.even the Gas regulator nuts seem cheap compared to the SA FALs
I must say ,of the kits I like the SA FALs the best

Brian in MN
September 19, 2001, 09:29
[QUOTE]Originally posted by gary.jeter:
The bolt locked-back after the shot. I inserted another round in the chamber, and tried to close the bolt by pulling downward on the BHO.


Gary, I bought a Springfield Armory M-1A in the mid 1980's. It came with some fairly extensive literature on firing this way. They had been getting complaints from customers blowing up their M-1A rifles. Their conclusion was always use the magazine for any self-loading rifle or handgun. In every case of failure they came to believe that the weapon fired before lockup. The bolt was simply traveling fast enough to set off a primer before the rifle locked.

It only takes one round to screw up a perfectly good rifle.