Gas port and feed ramp help

[vz58]

My scratch built 450 AR and 450 AK are getting close to being finished. I have reamed the barrels to with in a thousands or 2 and will have the head space finished when I have the correct headspace gauges sent (PTG sent non rebated rim guages)and I now need a pic of the AR feed ramp and a gas port diameter for the AR (16")

Would someone please help a guy out?

[Texas Sheepdawg]

This is a Job for Super WC...... Hey Catter? (It's hard to get his attention sometimes...Kind of like rattling a cage and moving around the cedar shavings ).

[wildcatter]

Shore,

On the ak, what did you do to increase the gas block size, to accommodate the larger barrel in that area? I mean, I too have a an ak/450 and also a sks/450, but I also increased the gas block ID diameter, just curious.

Feed ramp.. Look at this pic (http://www.google.com/imgres?q=feed+ram ... 33&bih=436), the six o'clock locking lug will need to be ground down to blend in with the other two 5.56 feed ramps, making one wide feed ramp for the 450, that is approximately 1/2" wide, for a .451 bullet.

I tried but failed to find a pic of our feed ramp, can someone try for me and include it here?

Porting.. I assume you have a set of numbered drills. Drill a small hole in the barrel, much smaller than you think is needed. The carbine length gas port of the 450b is about .091" +-, but you may want to start this exercise at say (assuming your ak gas port is at the same location as the ar), a #55 drill @.0520" (smaller if your gas block is closer to the chamber than the ar).

Using factory 450b ammunition, we'll discover the gas port size, by shooting and increasing the port size (one or two drill sizes at a time) until the bolt travels all the way rearward, "Reliably", (this will take some doing to determine on an ak, that does not have a bolt hold open device). When you've decided which drill size makes the action function reliably, then increase the drill size 4 sizes and that will be your combat function size. If you don't do this correctly and there is a very little room for error, the weapon will either be over gassed, which will damage the weapon or it won't function, as in short stroking, or it will become a jam-amatic.

Hope that helps..

..t

[vz58]

Thanks for the reply. On the AK the barrel diameter at the gb is .931". I will cnc a combination fsb and gb similar to a krink out of some 4140 I have on hand. I have done this before on a 45 win mag ak. I Considered doing it out of Fortal bit have not completely decided the issue. My removable front sight post will allow me drill the barrel gas port larger if needed without removing the gb.
As for the stroke on the ak, I have used thin masking tape placed over the charging handle slot and used an exacto to partially slit it. Once you fire the rifle just look at how far back the tape is split. If you dont scratch it deep enough the masking tape will rip and bunch up.