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Discussion Starter #1
With about 1/2 inch of play space between the bolt lock back position and the point of the Buffer Plate contacting the Buffer, has anyone tried inserting anything to add a layer of energy absorption in front of the Buffer?
250 or 300 thousandths worth of Belleville spring or an energy absorbing material like a high durometer Sorbothane washer might give some additional leeway to survive overgassing.
The question on the Sorbothane is if a high enough durometer rating can be achieved to survive getting pounded a few thousand times without shredding.
Thanks for any feedback / thoughts / criticisms.
 

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With about 1/2 inch of play space between the bolt lock back position and the point of the Buffer Plate contacting the Buffer, has anyone tried inserting anything to add a layer of energy absorption in front of the Buffer?
250 or 300 thousandths worth of Belleville spring or an energy absorbing material like a high durometer Sorbothane washer might give some additional leeway to survive overgassing.
The question on the Sorbothane is if a high enough durometer rating can be achieved to survive getting pounded a few thousand times without shredding.
Thanks for any feedback / thoughts / criticisms.
My gen1 RFB has a ~5/16" thick poly bumper on the front of the stop plate, yours doesn't?
 

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Discussion Starter #5
The hard polymer Buffer (Part #RFB-378) is squatting at the back of my Top Cover Weldment (Part #RFB-360) but I am wondering about adding something to help dissipate the impulse of the Buffer Plate (Part #RFB-340) striking the Buffer (or the Recoil Spring Nuts (Part #RFB-338) striking the back of the Top Cover Weldment). Of course, I assume the Kel Tec boys evaluated things like that when they did the design. Sorbothane (or equivalent) isn't cheap but it wouldn't break the bank either and it's not like the RFB was built to be the low cost alternative.
 

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There should be a poly bufferpad affixed into the back of the channel weldment. It dosn't stand out and you need a bright light to see it well.

The buffer plate on the back end of the guide rods rests against that buffer pad. When overgassed, the carrier strikes the plate which in turn compresses the pad.

Set properly the carrier should never touch it. The problem with adding any additional buffer mechanism is it would probably increase felt recoil. Any additional deceleration beyond the recoil spring may also interfere with the dynamics of the extraction/ejection so other design changes may be needed to compensate for that. I guess KT could have also left more room for overtravel, but then the RFB probably wouldn't be 27.5" long with an 18" barrel...
 

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Discussion Starter #7
There should be a poly bufferpad affixed into the back of the channel weldment. It dosn't stand out and you need a bright light to see it well.

The buffer plate on the back end of the guide rods rests against that buffer pad. When overgassed, the carrier strikes the plate which in turn compresses the pad.

Set properly the carrier should never touch it. The problem with adding any additional buffer mechanism is it would probably increase felt recoil. Any additional deceleration beyond the recoil spring may also interfere with the dynamics of the extraction/ejection so other design changes may be needed to compensate for that. I guess KT could have also left more room for overtravel, but then the RFB probably wouldn't be 27.5" long with an 18" barrel...
OK. That makes sense. I see now that the Buffer Plate is already sitting solidly against the Buffer (which is why you have to compress the Top Cover during assembly) so any additional absorption would have to sit between the front of the Buffer Plate and the back of the Carrier Channel Weldment. Since you need the back of the Carrier Channel Weldment open to get the Bolt in and out, the material would have to be attached to the front of the Buffer Plate.
It would only increase felt recoil if the Carrier Channel Weldment struck it, which would only happen if it was overgassed, which is the exact situation I am speculating on whether the additional material would be of any use in. The material would dissipate the impulse of the Carrier hitting the Buffer Plate somewhat and if it was less than 1/2 inch thick I would think it would only come into play during an overgas situation when the Carrier has already travelled beyond the distance needed for proper function. Return travel would still be controlled by the energy stored in the recoil springs and that energy would not be reduced by additional buffering in the "overtravel" zone. As a bonus, deterioration, and rate of deterioration, of the material would tell you if, and possibly give some indication of the extent, of overgassing.
Thoughts?
 

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My 2 cents:
It's cool that the RFB is so short, but it's not cool that you have to pay so much attention to adjusting the gas. Typically I end up with about the same setting every time. But you don't know until you go through the steps. And I really don't want to over-gas. So I go through the steps. (BTW, not to change the subject, but FYI the most change in setting seems to happen when the temperature shifts. Maybe the powder burns at a different rate).

As far as adding some energy absorbing material, the current design is so tight I can't see that working. But I do like the idea of side-stepping the gas adjustment via absorbing excess energy. Personally, I see this as maybe an easier path than an auto-gas-plug. But you need more space.
And it's not like the LOP is too long. In fact it's an inch shorter than typical. (That's why KT sells those buttpad spacers.) Perhaps a future generation RFB might have an additional mechanism to absorb excess carrier velocity. Just an extra inch on the rear with a built-in energy absorber (and a hole in the back of the channel for the mechanism to come through).
 

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I don't think I have really spent anymore time adjusting the gas for an ammo change than I have spent adjusting the sight for the POI change associated with that same ammo change... I have only ever experienced one overgass malfunction and that was when I was shooting a variety of ammo looking for the most consistent grouping. I prettymuch knew the change I needed to make, I just neglected to make it... I find that if I do my part, it runs great. Funny a lot of things in my life work that way:)
 

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Ronmar, that's a good point you make about needing to adjust the sights with an ammo change (or maybe a big temperature change). And what we get in return for doing this gas adjustment thing is one of the lowest recoil .308's around. Still, there's always room for improvement. My point is I'd trade an extra inch of length for a mechanism that absorbed excess carrier energy. But it's not something I feel I MUST have.
 
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