[schlaiek]

I am sure this question has been asked before, by my searching hasn't resulted in an fruitful answers.

Does different ammo require significantly different gas settings?

say I find the right setting for my match ammo that i shoot F-class with (moly coated 168 SMK, Lapura brass, Fed GM primer & 41.5gr TAC) and this setting results in a +10. I then want to shoot some 150g FMJ, or 168 V-max, or 168 FGM. will each ammo type require different gas settings? or is the system forgiving enough that all common ammo types (hand load or store bought) will work in a small range of gas settings.

again, I know this has probably been asked a million times but I want to make sure I understand what I am getting into before I pull the plug on a RFB.

thanks,
-Eric

 

[ronmar]

I am sure this question has been asked before, by my searching hasn't resulted in an fruitful answers.

Does different ammo require significantly different gas settings?
-Eric

Yes it will... How significant a change depends on the ammount of gas produced by the different load. The RFB in being made so short has very little room for bolt overtravel and buffering. Prettymuch all other gas operated rifles overgas and absorb the excess energy beyond that necessary to cycle the action with a buffering spring/mechanism. The RFB only has about 1/2" of overtravel and dosn't have much buffering(1/4" rubber pad) beyond that so it needs the precise ammount of gas delivered to the system to function properly. I think it is also the reason it is the softest shooting 7.62 I have ever fired...

With a manual adjustable gas vent, it will require a different setting to deal with the different ammount of gas produced by different loads... Once you know the setting needed for a particular ammo, it is fairly simple to change the setting when you change ammo. Once you get used to it, you can usually find a new gas setting for new/unknown ammo in 3-4 shots, at least I can now...

 

[akrobatik]

I have a dumb question regarding gas also.. Does the gas control the push of the shell casing out of the exiting slide. I hate to have to tilt my RFB after shooting in order to clear it of all of the empty shell casings. Is there a way to make the shell casing fly out of the RFB instead of the slow shell pooping effect, followed by a tilt of the gun at the end. Does anyone oil the exiting rail?

 

[ronmar]

I have a dumb question regarding gas also.. Does the gas control the push of the shell casing out of the exiting slide. I hate to have to tilt my RFB after shooting in order to clear it of all of the empty shell casings. Is there a way to make the shell casing fly out of the RFB instead of the slow shell pooping effect, followed by a tilt of the gun at the end. Does anyone oil the exiting rail?

No it dosn't... The shell ejection is powered by the carrier/bolt traveling forward. I find if I don't think about it, the empty casings take care of themselvs. My RFB hangs muzzle low on the sling, so any loose cases come out when I drop the gun onto the sling. I wouldn't put any lube in the channel. It isn't a wear point, and oil would only catch dirt/dust. It wouldn't help anyway, as the cases being loose in the channel is the reason they don't always fly out...

 

[schlaiek]

once a load has been found to work on a specific gas setting, is the gas setting consistent enough where you can "return to zero" on the gas setting with confidence on any/all ammo that is well built?


I ask because I'd only realistically develop a couple of loads for a RFB if I buy one. a general purpose 150g FMJ hand load and a 168g hunting bullet. if I knew one was setting 4, and the other 6 would it be just that simple, and repeatable to switch between the 2 loads, and the 2 settings?


on another topic, how does the Aug, FS2000, and any conventional rifle with a folding stock then handle recoil/gas without a gradual configuration like the RFB? I ask because I am not a rifle designer and my engineer's brain is curious why Keltec decided to go in this direction. is it the wave of the future?

 

[GFF]

Someone on here color coated their gas settings so they could easily just switch to the round they are using by painting dots on their gas plug and remembering which color was for which round.

 

[ronmar]

once a load has been found to work on a specific gas setting, is the gas setting consistent enough where you can "return to zero" on the gas setting with confidence on any/all ammo that is well built?


I ask because I'd only realistically develop a couple of loads for a RFB if I buy one. a general purpose 150g FMJ hand load and a 168g hunting bullet. if I knew one was setting 4, and the other 6 would it be just that simple, and repeatable to switch between the 2 loads, and the 2 settings?


on another topic, how does the Aug, FS2000, and any conventional rifle with a folding stock then handle recoil/gas without a gradual configuration like the RFB? I ask because I am not a rifle designer and my engineer's brain is curious why Keltec decided to go in this direction. is it the wave of the future?

Once broken in, the gas setting on mine so far has been very consistent...

Like I said in my first post, all other conventional gas operated rifles that I have ever played with over-gas, or send way more gas than is necessary to operate the action. Not sure what the FS2000 does as I have never had one apart... The excess energy beyond that necessary to cycle the bolt is absorbed into a spring and buffer mechanism, and ultimately your shoulder...