A2 receiver to A3 receiver - The Firearms Forum

stephen sams · 07-04-2010, 01:26 AM

I have a Bushmaster AR-15 with a A2 style receiver, I would like to change it to the A3 flat top style to be able to mount optics lower to the barrel bore. Would I be better off to purchase the A3 style receiver and have it installed, or purchase all of the needed equipment and learn to do my own work? thanks for your thoughts.

Helix_FR · 07-04-2010, 08:39 AM

stephen, it all depends on how mechanical you are. switching uppers receivers is not that difficult as long as you have a armorers wrench and a receiver block. i suggest you watch brownells series on building a upper to see whats involved also go to AR15.com and go to the do it yourself section. I only say this b/c I have run into people that own a ar but don't even know how to field strip it. Sounds to me that you are beyond that and have confidence in what your doing but I don't want you to get into a bad situation if things get confusing.

LonglineCharlie · 11-01-2010, 07:38 PM

I HAVE AN AR-15 A2 AND I JUST FOUND THAT MY CARRY HANDLE IS SPLIT LENGTHWISE. I CAN EITHER WELD IT OR CUT IT OFF AND PUT A PICATINNY ON TOP OF IT. I THINK TO DO THAT I WOULD HAVE TO MAKE A PIECE OF ALUMINUM WITH A 665 GROVE CUT IN THE MIDDLE OF IT TO STRADDLE THE RECIEVER. A 10-22 PICATINNY IS SIX INCHES LONG WITH 4 SCREWS THAT COULD HOLD IT TIGHTLY TO THE ALUMINUM BLOCK. IF THAT DID NOT RAISE IT HIGH ENOUGH FOR YOUR PARTICULAR SCOPE, GET HIGH SCOPE MOUNTS. I AM SURE MY 50 MM LENS WILL FIT GREAT. I WOULD REMOVE THE TOP OF THE FRONT SIGHT AS WELL AND PUT A FREE FLOATING FOREARM ON IT. ITS ALREADY A GREAT SHOOTING GUN AND A FREE FLOATING BBL SHOULD MAKE IT EVEN BETTER. ALL I HAVE TO DO NOW IS FIGURE HOW TO FASTEN THE ALUMINUM BLOCK TO THE RECIEVER SHORT OF WELDING IT ON THERE. POSSIBLITY THOUGH. THE TOP OF THE RECIEVER IS ONLY ABOUT .100 THICK. I CANNOT FIND OUT HOW TO MEASURE IT EXACT SO I WILL NOT REMOVE ANY OF THE TOP OF THE RECIEVER OTHER THAN THE CARRY HANDLE. WHAT DO YOU MEN THINK. HAVE ANY OF YOU DONE THIS TO YOUR AR?

wyoredot · 11-01-2010, 09:31 PM

My A-2 has the removable carry handle and I installed the Burris P.E.P.R. mount. You guys don't have that good fortune i'm guessing....

LonglineCharlie · 11-02-2010, 08:00 AM

WYORET, NO MINE IS PERMANENT. I BOUGHT MY AR ABOUT 20+ YEARS AGO. I DON'T REMEMBER WHERE I GOT THE SCOPE MOUNT THAT LAYS INSIDE THE CARRY HANDLE BUT IT MUST HAVE BEEN A LITTLE TOO WIDE CAUSING MY CARRY HANDLE TO SPLIT LENGTHWISE RIGHT IN THE CASTING SPLITLINE. I NEVER LIKED THE SCOPE BEING THAT HIGH ABOVE THE GUN AND IF POSSIBLE I AM GOING TO REMOVE IT AND PUT A PICATINNY SCOPE MOUNT ON IT. MY ONLY OTHER ALTERNATIVE IS TO SPENT A COUPLE OF HUNDRED DOLLARS FOR A NEW UPPER RECIEVER BUT I DO NOT HAVE $200 TO THROW AWAY IF I CAN GET THE SAME RESULTS FOR $20

LonglineCharlie · 11-02-2010, 03:30 PM

WELL I HAVE FOUND THAT I CAN BUY A FLATOP RECIEVER FOR $99. OR AN ADAMS FOR $119. I CAN MAKE THE WRENCH TO TIGHTEN THE FOREARM NUT. I WOULD LIKE TO PUT A FREE FLOATING FOREARM ON IF IT STILL DOES NOT WANT TO SHOOT LIKE I KNOW IT CAN. FROM WHAT I HAVE READ, I AM NOT SURE I WANT A PISTON BUT THE ADAMS UPPER RECEIVER, IS SET UP WITH A GROVE ALREADY FOR THE PISTON SHOULD I WANT TO GO THAT ROUTE SOME DAY. I HAVE NOT HAD A LOT OF TROUBLE WITH DIRTY ACTIONS THOUGH AND THEY SAY THE PISTON DOES NOT SHOOT AS GOOD AS THE GAS. I ASSUME THAT IS BECAUSE OF THE VIBRATION CAUSED BY THE TUBE MOVEMENT TO THE ACTION AFFECTING THE DAMPENING OF THE BARREL?? AM I RIGHT ON THAT? LONGLINE CHARLIE

07-04-2010, 01:26 AM	#1
stephen sams Member Join Date: Jun 2010 Posts: 8	A2 receiver to A3 receiver I have a Bushmaster AR-15 with a A2 style receiver, I would like to change it to the A3 flat top style to be able to mount optics lower to the barrel bore. Would I be better off to purchase the A3 style receiver and have it installed, or purchase all of the needed equipment and learn to do my own work? thanks for your thoughts. --> Last edited by stephen sams; 07-04-2010 at 01:28 AM..

07-04-2010, 08:39 AM	#2
Helix_FR TFF Moderator/Host Join Date: Apr 2009 Location: Imperial, MO Posts: 3,621	Re: A2 receiver to A3 receiver stephen, it all depends on how mechanical you are. switching uppers receivers is not that difficult as long as you have a armorers wrench and a receiver block. i suggest you watch brownells series on building a upper to see whats involved also go to AR15.com and go to the do it yourself section. I only say this b/c I have run into people that own a ar but don't even know how to field strip it. Sounds to me that you are beyond that and have confidence in what your doing but I don't want you to get into a bad situation if things get confusing. __________________ Only cowards shoot with their eyes closed.... helixgunsmith.com

11-01-2010, 07:38 PM	#3
LonglineCharlie Member Join Date: Oct 2010 Location: FAIRLAND, INDIANA Posts: 21	Re: A2 receiver to A3 receiver I HAVE AN AR-15 A2 AND I JUST FOUND THAT MY CARRY HANDLE IS SPLIT LENGTHWISE. I CAN EITHER WELD IT OR CUT IT OFF AND PUT A PICATINNY ON TOP OF IT. I THINK TO DO THAT I WOULD HAVE TO MAKE A PIECE OF ALUMINUM WITH A 665 GROVE CUT IN THE MIDDLE OF IT TO STRADDLE THE RECIEVER. A 10-22 PICATINNY IS SIX INCHES LONG WITH 4 SCREWS THAT COULD HOLD IT TIGHTLY TO THE ALUMINUM BLOCK. IF THAT DID NOT RAISE IT HIGH ENOUGH FOR YOUR PARTICULAR SCOPE, GET HIGH SCOPE MOUNTS. I AM SURE MY 50 MM LENS WILL FIT GREAT. I WOULD REMOVE THE TOP OF THE FRONT SIGHT AS WELL AND PUT A FREE FLOATING FOREARM ON IT. ITS ALREADY A GREAT SHOOTING GUN AND A FREE FLOATING BBL SHOULD MAKE IT EVEN BETTER. ALL I HAVE TO DO NOW IS FIGURE HOW TO FASTEN THE ALUMINUM BLOCK TO THE RECIEVER SHORT OF WELDING IT ON THERE. POSSIBLITY THOUGH. THE TOP OF THE RECIEVER IS ONLY ABOUT .100 THICK. I CANNOT FIND OUT HOW TO MEASURE IT EXACT SO I WILL NOT REMOVE ANY OF THE TOP OF THE RECIEVER OTHER THAN THE CARRY HANDLE. WHAT DO YOU MEN THINK. HAVE ANY OF YOU DONE THIS TO YOUR AR?

11-02-2010, 08:00 AM	#5
LonglineCharlie Member Join Date: Oct 2010 Location: FAIRLAND, INDIANA Posts: 21	Re: A2 receiver to A3 receiver WYORET, NO MINE IS PERMANENT. I BOUGHT MY AR ABOUT 20+ YEARS AGO. I DON'T REMEMBER WHERE I GOT THE SCOPE MOUNT THAT LAYS INSIDE THE CARRY HANDLE BUT IT MUST HAVE BEEN A LITTLE TOO WIDE CAUSING MY CARRY HANDLE TO SPLIT LENGTHWISE RIGHT IN THE CASTING SPLITLINE. I NEVER LIKED THE SCOPE BEING THAT HIGH ABOVE THE GUN AND IF POSSIBLE I AM GOING TO REMOVE IT AND PUT A PICATINNY SCOPE MOUNT ON IT. MY ONLY OTHER ALTERNATIVE IS TO SPENT A COUPLE OF HUNDRED DOLLARS FOR A NEW UPPER RECIEVER BUT I DO NOT HAVE $200 TO THROW AWAY IF I CAN GET THE SAME RESULTS FOR $20

11-02-2010, 03:30 PM	#6
LonglineCharlie Member Join Date: Oct 2010 Location: FAIRLAND, INDIANA Posts: 21	Re: A2 receiver to A3 receiver WELL I HAVE FOUND THAT I CAN BUY A FLATOP RECIEVER FOR $99. OR AN ADAMS FOR $119. I CAN MAKE THE WRENCH TO TIGHTEN THE FOREARM NUT. I WOULD LIKE TO PUT A FREE FLOATING FOREARM ON IF IT STILL DOES NOT WANT TO SHOOT LIKE I KNOW IT CAN. FROM WHAT I HAVE READ, I AM NOT SURE I WANT A PISTON BUT THE ADAMS UPPER RECEIVER, IS SET UP WITH A GROVE ALREADY FOR THE PISTON SHOULD I WANT TO GO THAT ROUTE SOME DAY. I HAVE NOT HAD A LOT OF TROUBLE WITH DIRTY ACTIONS THOUGH AND THEY SAY THE PISTON DOES NOT SHOOT AS GOOD AS THE GAS. I ASSUME THAT IS BECAUSE OF THE VIBRATION CAUSED BY THE TUBE MOVEMENT TO THE ACTION AFFECTING THE DAMPENING OF THE BARREL?? AM I RIGHT ON THAT? LONGLINE CHARLIE