JP Rifles AR-15 FMOS Bolt Carrier Not Compatible with Geissle National Match Triggers

[Fire4EffectCA]

What would be the best option for a Mil-Spec AR-15 bolt carrier for use with a JP Rifles enhanced bolt? I have found that the JP Rifles full mass bolt carrier I received with the JP Rifles enhanced bolt is not compatible with the Geissele National Match trigger. The hook under the face of the Geissele National Match hammer is hanging up on the tail of the JP Rifles full mass bolt carrier. A Daniel Defense bolt carrier will work Geissele National Match trigger, but they don’t sell the bolt carrier separately.

 

[TonyTheTiger]

Were I in your position and already had all these parts I'd try to measure the hammer hook interference and decide if I could live with removing a little bit of the hook.

 

[Fire4EffectCA]

Were I in your position and already had all these parts I'd try to measure the hammer hook interference and decide if I could live with removing a little bit of the hook.

Actually what I need is ether the longer hammer face of the SSA-E hammer or material added to the back of the JP Rifles bolt carrier so it replicates the Daniel Defense bolt carrier.

I have discussed this at length with both JP Rifles and Geissele staff. Based on my observations they concluded the combination was not compatible.

 

[TonyTheTiger]

Ah, I misunderstood where the interference was happening.

 

[msgriff]

Actually what I need is ether the longer hammer face of the SSA-E hammer or material added to the back of the JP Rifles bolt carrier so it replicates the Daniel Defense bolt carrier.

I have discussed this at length with both JP Rifles and Geissele staff. Based on my observations they concluded the combination was not compatible.

Great post, explanation and visuals.

I wonder if the JP carrier is the sole outlier, or if this is something that might be hit or miss with other carriers. The dimension of the body of the carrier, measured from the front, that seems relevant looks like 2.81" on a M16 carrier drawing.

 

[Fire4EffectCA]

Great post, explanation and visuals.

I wonder if the JP carrier is the sole outlier, or if this is something that might be hit or miss with other carriers. The dimension of the body of the carrier, measured from the front, that seems relevant looks like 2.81" on a M16 carrier drawing.

I know the Daniel Defense bolt carrier works, but it is Mil-Spec.

 

[Stone111]

I use LWRC's one piece bolt carriers with JP's AR15 bolts, I miced it for you and at that spot its .082" I also run a Cryptic coatings BCG in another rifle and its the same as the LWRC. Both of those are milspec BCG's and I suspect the DD BCG maybe an outlier and an anomily. Personally I would dump that trigger and move on...

https://www.lwrci.com/LWRCI-Direct-Impingement-Bolt-Carrier-Carrier-Only_p_223.html

If you can, check the dimensions at that spot on both the DD and JP BCG and post it up, I am curious.

 

[Fire4EffectCA]

I use LWRC's one piece bolt carriers with JP's AR15 bolts, I miced it for you and at that spot its .082" I also run a Cryptic coatings BCG in another rifle and its the same as the LWRC. Both of those are milspec BCG's and I suspect the DD BCG maybe an outlier and an anomily. Personally I would dump that trigger and move on...

https://www.lwrci.com/LWRCI-Direct-Impingement-Bolt-Carrier-Carrier-Only_p_223.html

If you can, check the dimensions at that spot on both the DD and JP BCG and post it up, I am curious.

I just remembered I have an early 1990’s vintage Colt Competition HBAR that I installed a Geissle National Match Trigger in around 2010. I have not shot it in over a decade. It cycles fine. The profile on the back of this Colt bolt carrier where the hammer rides is identical to the Daniel Defense bolt carrier. According to Geissle their National Match trigger was designed for service rifle competition with a Mil-Spec bolt carrier.