Single vs double cam bolts n carriers

[Armsdad]

I have been asked about this. And this is what I think on the matter. If I'm wrong or sombody can add to it be my quest. The difference in single and double cam bcg..Im pretty sure the Indian bolts and carriers are all single cam. Some early trials bolts are single cam. I have seen more single cam fn fal carriers than I have bolts . I'm not sure what will work in what but here are the differences that I see. If you just want to know what the terms single and double cam means. And sombody showed me this a few yrs ago, so I'm not a genius by any means. I think ChiefArt showed me this.

 

[L Haney]

I have no idea where this is going. Are you talking about bolt lockup when in battery?

 

[hkshooter]

Is there a question here?
As far as use, they will both swap with no problems, in my experience.

 

[OLDMANPBK]

A couple of pictures I saved by embatp.
Single cam L double cam R.

 

[embatp]

The Israelis I believe said only mix the two if you had no other option….they will work together….and they are early parts….not sure when they made the change…

 

[Armsdad]

I have been asked what the difference was a few times and this is all I knew about it. Just figured Id post how they look different and let smarter people tell the story. If you can even go by the Indian stuff I had an Indian carrier that a regular brit l1a1 bolt didn't slide smoth in just working it by hand out of the gun..could put the single cam Indian bolt back in and It worked better. So I wasn't sure if it matters. But that's all I know is how to tell the difference in the 2 is why I posted the pics. For info and any added info appreciated.

 

[riceeater25]

It was I that brought up the question to Armsdad. Currently on building an Israeli trials FAL and was wondering if there was ever a single cam bolt that was used with Israelis. I have seen plenty of Israeli single cam carriers and would make sense they pair up with a single cam bolt; however, I have yet to see one single cam Israeli bolt.

Have a '55 Israeli double cam bolt and a '56 Israeli single cam carrier on the way. Did single cam bolts get phased out before single cam carriers did? Pics of said bolt and carrier.

 

[Armsdad]

The bolt I have now that's single cam is from a Canadian trials fal. Ex1 maybe 54 or 55 can't remember , I don't build the Canadian stuff it's too expensive. Im thinking the bolts were phased out and the carriers are still going. When I was talking earlier about swapping out the Indian stuff. It coulda been an Indian bolt in a brit carrier that was rough or the other way around it's been a few yrs. But one way was not as good a fit. Since I see more single cam carriers I'm guessing that's the one you can use with either kind of bolt ..But mainly I just use whatever I got that works. I match up stuff best I can and let it go. Sometimes if the #'s don't match anyhow I will swap out several bolts to headspace until I find what headspaces good with whatever Locking shoulder I have. Im not ocd. But I do keep matching # stuff together If I have it.

 

[embatp]

A lot of the Izzy single cam carriers were later modded to work with double cam bolts…I suspect some mods were done better than others…

 

[otis61]

That's interesting. I'm working on an early Izzy also. I just looked at the bolt and carrier, and the bolt is double and the carrier is single cam. Both are 1955.

 

[riceeater25]

Saw some interesting variation between early Israeli bolt and carriers as well. Maybe these are from the initial contract (B stocks). The carriers are sanitized, but saw a few bolts with 1XXXX serial on them as well (https://www.falfiles.com/threads/fal-oddities-i-received-in-my-israeli-kits.455779/). Some were marked with a Hebrew letter on the top like the one I have but not all. Not sure what that means.

To my understanding, trial FALs are below 2000. It seem the ASR dual marks ends at around that range while the serial continues (https://www.falfiles.com/threads/israeli-type-a-lowers.359880/).

 

[otis61]

It was I that brought up the question to Armsdad. Currently on building an Israeli trials FAL and was wondering if there was ever a single cam bolt that was used with Israelis. I have seen plenty of Israeli single cam carriers and would make sense they pair up with a single cam bolt; however, I have yet to see one single cam Israeli bolt.

Have a '55 Israeli double cam bolt and a '56 Israeli single cam carrier on the way. Did single cam bolts get phased out before single cam carriers did? Pics of said bolt and carrier.

View attachment 333238 View attachment 333244
View attachment 333240 View attachment 333245

My bolt has the same mark on the spin as yours.

 

[gunplumber]

There are three types of bolt cams and two types of carrier cams.
Second model the sides of the cam are rounded.
The FN armorer manuals says matching the cam is "preferred" but not required.

Note the two variations of single cam bolts also have 1-piece extractor. I don't know if this is "all" have 1-piece extractors.