M1 Garand throat erosion gauge use?Also M16 headspace?

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stantheman1986	M1 Garand throat erosion gauge use?Also M16 headspace?	Lead	[-]
Posts: 5047 (07/09/08 12:14 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Tags : None How do you properly use the M1 throat erosion gauge? It seems like the follower gets in the way of inserting the gauge, do you have to keep it pushed down when you insert it? Also, do you read the number that's even with the top of the receiver or the last number visible before the chamber? It's hard to tell which number is actually the throat erosion....the Danish rack grade I measured last night seemed to read a "5". I also wanted to know if this gauge could be used for 1903's too, or is it just for the Garand? On another topic, I have a 5.56 field gauge for the AR15/M16 rifle, that I got just to make sure the bolt assemblies I install at least pass a field gauge, considering these are surplus M16 uppers and not new. Do you have to take the extractor off, and then is it like a bolt gun where if the M16 bolt closes all the way on the field gauge then it's a "fail"? I'm new to the throat erosion gauge and also have never done headspace on a semi-auto much less an M16, just bolt rifles, so I would appreciate any advice.
RichieRich3902		#1	[-]
Posts: 1257 (07/09/08 03:40 PM) Host Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Stan the M1 gauge is read where it is visible from the top of the receiver, you do need to push the follower down a little to use it. For the headspace gauge you must still take the extractor and ejector out and use it stripped, just like any other bolt. I imagine that they will all pass head spacing it's hard for an M16/AR-15 to be out of spec. Cowards die many times before their deaths; The valiant never taste of death but once. -William Shakespeare, Julius Caesar
stantheman1986	Thanks	#2	[-]
Posts: 5050 (07/09/08 08:08 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Thanks for the info, I was wondering how to use that throat erosion gauge. I figured I would be on the safe side with the headspace gauge, given that I am putting unknown used bolts into an M16 that has been through who knows what in military or civilian hands! I have seen the abuse and wierd stuff that happens to M4's and M16's
Orlando.curioandrelicfi...		#3	[-]
Posts: 4 (07/09/08 09:47 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Whatever number is visible is the reading, it cannot be used on the 1903
stantheman1986	1903	#4	[-]
Posts: 5054 (07/10/08 07:16 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Thanks for the info, I found a "rough estimate" way to use it for an 03, but you need a minty-barreled 03 to use as a comparison to make it work. I have a Springfield manufactured 03, rebuilt with a HS barrel that looks to have been never fired after the rebuild. Also has an 03A3 bolt, my guess is a post-war or late war rebuild that got sent to Greece and never issued......anyway I used the reading from this barrel and compared it to my more-used 03 and 03A3 and was able to tell that these rifles had less "life" left in the barrels. In my opinion the throat erosion is less critical in 03's than it is in Garands which are much more susceptible to throat wear, especially if they were used and abused in Denmark or Greece with rapid firing or sustained firing in training. 03's just can't generate the heat in the throat to cause rapid erosion.
Jeremy2171		#5	[-]
Posts: 2107 (07/14/08 09:45 AM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	If your 5.56 gage is GI you don't need to strip the bolt. Drop it in the chamber, with the rifle broke down shotgun style. Then with muzzle down see if the bolt/carrier fully closes....you should be able to see if it still sticks up past the edge of the upper rec. If it closes switch the bolts around see if that helps. In my years of doing this I've only found one barrel that wouldn't headspace on a new bolt so you will probably be ok. Check billricca.com for an 03 barrel erosion gage I think he still has them.
RichieRich3902		#6	[-]
Posts: 1258 (07/14/08 07:14 PM) Host Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Thanks Jeremy, now I'm educated too. Cowards die many times before their deaths; The valiant never taste of death but once. -William Shakespeare, Julius Caesar