modded uppers

ARlife4me

Well-Known Member
Joined
Apr 18, 2018
Messages
3,389
Location
Texas
With far and few short mag uppers with a larger than 308win case ejection ports, who has modded their own or bought a well quality control receiver? KAK is NOT that well for QC on uppers and lowers in my experience. I have 2 AP uppers coming next week (hopefully) to be Dremeled out. I care nothing about the use of the port cover if needing to enlarge the upper portion where the cover latches. Not sure at this point to know when is too much enlarged, but making sure not to get into the bcg raceway.
 
Measure twice and cut once! Personnally I don't use a dremel or hand held anything for precision metal removal. I'm lucky enough to have access to a CNC vertical mill and I bought special milling bits to deal with super hard aircraft forged aluminum. I just know enough about machining to be scary. At the shop and I often ask a true machinist about this or that like what is the best way to mount this up and advice on cutting speed and depth of each cut. I'm just a team member for historic car racing mechanic to afford my long time racing and lifestyle.

My advice is to get a machinist to make some really nice looking funtional cuts!

I just took an empty 308 and placed it in my ar10 ejection slot and it has lots of room. Later on today after work I will compare a 300 wsm case to my ar10 or get out a caliper and measure the width and the case size for the WSM
 
Last edited:
Measure twice and cut once! Personnally I don't use a dremel or hand held anything for precision metal removal. I'm luck enough to have access to a CNC vertical mill and I bought special milling bits to deal with super hard aircraft forged aluminum. I just know enough about machining to be scary. At the shop and I ask a true machinist about this or that like what is the best way to mount this up and advice on cutting speed and depth of each cut. I'm just a team member for historic car racing mechanic to afford my long time racing and lifestyle.

My advice is to get a machinist to make some really nice looking funtional cuts!

I just took an empty 308 and placed it in my ar10 ejection slot and it has lots of room. Later on today after work I will compare a 300 wsm case to my ar10 or get out a caliper and measure the width and the case size for the WSM
While I don't have ocd I don't mind others doing fitting/machining if I don't have the tools. Being close as to drop off the part(s) for work I don't want to ship it off 100's of miles away. I do understand that a drimmel isn't the best for this kinda job and not near as accurate as a precision machine. Man! I need to win the lotto! Measuring 2 uppers I have (1 for 308 based & 1 for short mags) there seems to be the same amount of clearance (+.090")
 
My 308 can drop in and fall out a 7mm Rem mag with the belt diameter of .528. My caliper reading on the ejection port width is .553

I couldn't find any of the 300wsm that I reloaded for a friend.

20231213_131210.jpg


20231213_131350.jpg
 
Just rechecked mag and non ejection ports.
magnum .644" which gives .100" clearance with 7saum
non (308win bases) .582" which gives ~.120" clearance.
 
Top