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I know this has been ridin hard and put away wet. I was seaching the forum for the directions and pics on how to correctly measure the bolt gap on my ptr-91. I could not find the pics or instuctions, just alot of flames on what bull crap has been brought up about it. If anyone knows the link, please let me know. I just wanted to check mine and know how to do it. Thanks!
 

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I know this has been ridin hard and put away wet. I was seaching the forum for the directions and pics on how to correctly measure the bolt gap on my ptr-91. I could not find the pics or instuctions, just alot of flames on what bull crap has been brought up about it. If anyone knows the link, please let me know. I just wanted to check mine and know how to do it. Thanks!
It's really quite easy. First, clear the weapon. You know the drill - Put the gun on safe. Pull the cocking handle back and move it to the locked open position. Remove the magazine. Visually inspect that there's no round in the chamber. Reach into the magwell and stick your finger into it to physically be sure there's no round in the chamber.

Now, use the "HK slap" and let the cocking handle snap forward.

Move it to Fire and pull the trigger so the hammer snaps against the bolt.

Now stick a feeler gauge through the mag well opening, and put it between the bolt carrier and the bolt head. Start with .010". Can you get it in? If so, move up to .012". If not, drop to .008". You want to keep changing to thicker or thinner feeler gauges until you find the one that can be inserted into the gap between the bolt carrier and bolt head with some 'drag'. Basically, keep goin up until you can't insert the gauge, then go down one thickness. If you can get that one in, then that is your bolt gap. Acceptable gap is .1mm - .5mm. If you don't have metric feeler gauges, 1mm = .0393700787", so you can round to .004" to .020". And it at first seems counter-intuitive, but bigger gap = less wear.

If you look at the picture below, you can see the gap you're measuring. It is the space between the front of the flat wide surface on the bottom of the bolt carrier on the right, to the back of the bolt head. It's the space between the two parts right in the center of the picture. In this case, they are fully separated, so the gap is huge, like .25". When the rollers are engaged in the trunnion and the bolt carrier is pushed forwards, the gap drops down to the very narrow one you will be mearuring.

 

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Thank you so much for taking the time to explain and post pics. I am going to pull it out tonihjt and check it.
 

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I just checked it and got .0125. I guess that is pretty good. Thanks again for explaining it in detail.
 

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This forum is great. Finally got around to check my bolt gap and after 120 rounds or so my gap is at .018". Hope it stays like this
 
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