Issues with the Bolt-Hold-Open Device

This article is a full explanation of issues I have experienced using my Tavor TAR-21 rifle with Magpul’s very popular PMAG series of magazines.

But for those who don’t want to read the full thing, here is the most important points:

I have had my bolt-hold-open device damaged during my first winter shooting the Tavor, and experienced failure to feed issues.

I have filed down the rear profile of my PMAGs to square the rear profile of the feedlips to match a USGI mag.

This is a 3 minute modification that can be done with a hand file. It does not affect the PMAGs use in any other firearm.

It likely does weaken the feedlips of the magazine. I would rather weaken a $20 magazine than damage an expensive rifle.

I cannot state with certainty that PMAGs caused this damage. But I do not have problems anymore. It appears that there are zero issues with the IWI US SAR-21 rifles at this time!


With all those points out of the way, I can guide you through the same process that led to me making those changes. In my first winter shooting the Tavor, probably within the first thousand rounds or so I experienced a failure to feed. The person I was shooting with, a service member and veteran of Afghanistan, suggested that a more solid lubrication for winter shooting was in order. While looking up different malfunctions with piston operated rifles, I stumbled across the now well known video detailing issues with FN’s Scar 17 rifle and the Magpul PMAG.

I could see that the bolt-hold-open device lifted quite high in the Scar, and thought I had better try it in my similarly designed by rarer Tavor. Sure enough, I could see a tiny movement in the bolt hold open device when I inserted a loaded magazine. Or could I? Sometimes I was certain it was there, other times it seemed like there was only the click of the mag and no movement at all.

That led to me making this rather unhelpful video you see below:

That spring, on multiple occasions out shooting in fairly remote areas, I experienced failure to feeds and double feeds in the rifle with disturbing regularity. I documented those issues and requested help in this video here:

I had various suggestions and support from other Tavor owners. Some suggesting that there was something wrong with my bolt, or my gas system was short stroking, or that the PMAGs were still an issue. In response to this concerning decline in reliability I did 3 things:

I switched my military bolt with its free floating firing pin to a civilian bolt and spring loaded firing pin. When doing this I noticed unusual wear points developing on the military bolt I had used for my first two thousand rounds.

Tavor TAR21 bolt
Tavor Tar21 mil and civ bolts

I thoroughly cleaned my gas piston and as much inside the gas system as I could get.

And I filed down my pmags beyond the light dremeling I’d done previously. I squared them firmly into an identical profile of a USGI mag.

I have not had a problem since. However, when advising other Tavor shooters to do the same to their PMAGs there was some debate. Some people report seeing a movement in their bolt hold open, some do not. Some very knowledgeable people still say it is impossible for the PMAG lips to bump the bolt-hold-open high enough to touch the bolt as it fires.

In order to lay things out as clear as possible I made this video:

When making that video I discovered the extent of the damage to my bolt-hold-open device. You can clearly see marks where it has been scraped by the bolt closing.

Tavor TAR21 bolt hold open

For me, fixing the pmags is a simple process that makes me rest easy knowing they cannot be interfering with my rifle. I would rather be safe than sorry when it comes to things like this.
Tavor Bolt Hold Open Closeup

As a final note, it is possible that the bolt hold open was damaged by two things: the rounded rear profile of the PMAGS and using the magazine as a rest in my early days of shooting. I have heard enough stories about what resting on a magazine can do to accuracy or reliability to know now that it is a bad idea. Perhaps a combination of Magpul’s design and my behaviour is to blame.

I have another bolt hold open on order, which I trust will not see damage. If you have direct personal experience with reliability issues in the Tavor, I’d love to hear from you.

I remove the highlighted portion on all my polymer mags: