Question about bolt on Angstadt Arms UDP-9

[jacotsmith]

Hi everyone,

I picked up a used Angstadt Arms UDP9 and it came with a little baggie containing an insert (and retaining roll pin) for the bolt.



We're I to install it I imagine it would considerably increase the bolt's mass. I haven't shot it yet but hoped somebody on here could let me know what it's for and if I need it.

Thanks!

 

[Kratos]

A blowback system requires more weight to balance the rearward force on the BCG, buffer, and buffer spring. I’m not sure why it’s removable, other then to use it with Buffer systems like a JP SCS.

 

[jacotsmith]

Hmm thanks. The rifle came with a folding stock adaptor but that shouldn't make a difference I don't think. Unless someone else can chime in I might just have to try firing the rifle without it. There is zero wear, but that might just be because it's an internal part and shouldn't move when installed properly.

Anyone else?

 

[jacotsmith]

For the benefit of anyone else searching this thread in the future, this bolt was on a rifle with a Law Tactical folding stock adapter. The weight is meant to be installed if the folder is removed, as it is the same mass as the adapter. So there.

 

[IIIIII]

you cant have the folder and that weight at the same time since the weight will not allow you to insert the extender into the bolt. The theory is that the extender will make up for the lost bolt weight, (but it will be a 2 Oz lower overall bolt weight). It will work fine without the weight. Angstadt suggests to make up the difference with the buffer weight but it still works fine without it.

 

[Bartok5]

Reduced Bolt Carrier Group mass will result in increased operating velocity, which could conceivably lead to function problems if (for instance) the action cycles faster than the magazine can lift new ammo into the feed-path. That said, if function is reliable you may find that perceived recoil is less than with the full-mass Bolt-Carrier Group in a straight blow-back action.