Transitional Bolt Stop

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[ARCHIVED THREAD] - Transitional Bolt Stop

Posted: 2/15/2017 10:55:05 PM EDT

Has anyone seen a bolt stop like this? My guess it's a "transitional" 602 to 604 bolt stop.....I couldn't find anything in the "Black Rifle" book. Found it on an in-use Air Force M16A2.

Posted: 2/15/2017 11:03:34 PM EDT

[#1]

Pics? Is it the one that looks like the current design but with the extra serrations?

Posted: 2/15/2017 11:22:16 PM EDT

[#2]

Quoted:
Has anyone seen a bolt stop like this? My guess it's a "transitional" 602 to 604 bolt stop.....I couldn't find anything in the "Black Rifle" book. Found it on an in-use Air Force M16A2.

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They came out AFTER the 602 and were used on early 604's and XM16E1's

Attached File

Posted: 2/15/2017 11:33:53 PM EDT

[#3]

NOW the pics are showing for me.

Posted: 2/16/2017 12:23:35 AM EDT

[#4]

What on earth was the point of that, looks? Would make more sense to put them on the tiny hold open nub as some mfgrs have started doing.

Posted: 2/16/2017 12:30:45 AM EDT

[#5]

Quote History

Quoted:
What on earth was the point of that, looks? Would make more sense to put them on the tiny hold open nub as some mfgrs have started doing.

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Maybe the thought was that you could use the rim of a cartridge case to activate the bolt lock if it was finicky, and the milled lines would give it more "bite"

Posted: 2/16/2017 12:35:43 AM EDT

[#6]

Quote History

Quoted:
What on earth was the point of that, looks? Would make more sense to put them on the tiny hold open nub as some mfgrs have started doing.

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I think that's where they intended your thumb to press. If you watch the old training videos they always work the rifles very gingerly. In actual use you are just slapping them around. Like with the dimpled pins, the thought was so you could use the tip of a bullet to push them out all nice. I'm sure in reality guys would just punch them out with a knife or something then pull it the rest of the way out.

Posted: 2/16/2017 12:41:04 AM EDT

[#7]

All I know is I wish I could find one that didn't cost a fortune.

Posted: 2/16/2017 1:10:12 AM EDT

[#8]

Correction on above info. They came out during 602 production. We have a member with an original 602 with known past ownership and history. No parts were ever changed and it wears a transitional bolt stop.

Posted: 2/16/2017 1:13:39 AM EDT

[#9]

Thanks for the info.....every so often I run into a few USAF M16A2's with 601/602/603/604 parts still mixed into them.....

Posted: 2/16/2017 1:22:11 AM EDT

[#10]

Quote History

Quoted:
Correction on above info. They came out during 602 production. We have a member with an original 602 with known past ownership and history. No parts were ever changed and it wears a transitional bolt stop.

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The parts guide sticky AND retro black rifle have not been updated in YEARS. Are the authors still members here? If not, could a moderator give edit abilities to the parts guide sticky to someone who IS a member?

Posted: 2/16/2017 1:25:01 AM EDT

[#11]

Quote History

Quoted:
Thanks for the info.....every so often I run into a few USAF M16A2's with 601/602/603/604 parts still mixed into them.....

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There is NO WAY that I could work in an armory, since I would constantly be tempted to swap out parts and pieces. I would not do it, but I would not like the temptation either.

Posted: 2/17/2017 12:01:45 AM EDT

[#12]

My take on them from a manufacturing stand point is that the serrations on the transitional stops were vestigial.
The original bolt stops just had the serrated lower. When the change to the bumped up lower end came thru they just went back in the mold and added that detail.
It was a subtractive operation in that they removed metal from the mold to add the bump. Then when the molds wore out and new ones were made the serrated detail was left off of the new molds.

Posted: 2/17/2017 12:08:41 AM EDT

[#13]

Quote History

Quoted:
All I know is I wish I could find one that didn't cost a fortune.

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John Thomas @ Retro Arms Works sells reproductions for $50.

Posted: 2/17/2017 9:11:39 AM EDT

[#14]

Well, in the Army we had MWO(mandatory work orders) to give you the reason to fix that. Buy some take down an pivot pins an bolt catches. Update the rifles as they come in or during inventory. Seeing those old bolts an bolt carriers makes me think those rifles never get the yearly depo (higher level) inspection. Using a 1965 bolt group in a 2000-isn A2 barrel for a go gun

Zoomies

Posted: 2/17/2017 9:43:17 AM EDT

[#15]

Quote History

Quoted:
Well, in the Army we had MWO(mandatory work orders) to give you the reason to fix that. Buy some take down an pivot pins an bolt catches. Update the rifles as they come in or during inventory. Seeing those old bolts an bolt carriers makes me think those rifles never get the yearly depo (higher level) inspection. Using a 1965 bolt group in a 2000-isn A2 barrel for a go gun

Zoomies

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What became of the old and obsolete parts that you removed?

Posted: 2/17/2017 3:15:57 PM EDT

[#16]

Quote History

Quoted:
My take on them from a manufacturing stand point is that the serrations on the transitional stops were vestigial.
The original bolt stops just had the serrated lower. When the change to the bumped up lower end came thru they just went back in the mold and added that detail.
It was a subtractive operation in that they removed metal from the mold to add the bump. Then when the molds wore out and new ones were made the serrated detail was left off of the new molds.

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Never stopped to think about this, but that makes sense. I appreciate your insight, h'n'b!

Posted: 2/17/2017 7:30:37 PM EDT

[#17]

Quote History

Quoted:
Well, in the Army we had MWO(mandatory work orders) to give you the reason to fix that. Buy some take down an pivot pins an bolt catches. Update the rifles as they come in or during inventory. Seeing those old bolts an bolt carriers makes me think those rifles never get the yearly depo (higher level) inspection. Using a 1965 bolt group in a 2000-isn A2 barrel for a go gun.

View Quote

MWO is Modification Work Order, Annual inspections and gaging are done by Direct Support under the old maintenance system which is now known as Field Maintenance under the new system. Depending on the recoverability code, demil code or controlled item inventory code determines what you can throw in the trash, have to mutiliate or, turn into to DRMO for demilitarization. Anymore, unless it is a pin, spring or screw, you have to turn in the unserviceable (old) part to clear the new part in the supply system.

Wpns Man

Posted: 2/17/2017 8:48:46 PM EDT

[#18]

Quote History

Quoted:

MWO is Modification Work Order, Annual inspections and gaging are done by Direct Support under the old maintenance system which is now known as Field Maintenance under the new system. Depending on the recoverability code, demil code or controlled item inventory code determines what you can throw in the trash, have to mutiliate or, turn into to DRMO for demilitarization. Anymore, unless it is a pin, spring or screw, you have to turn in the unserviceable (old) part to clear the new part in the supply system.

Wpns Man

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Quote History

Quoted:

Quoted:
Well, in the Army we had MWO(mandatory work orders) to give you the reason to fix that. Buy some take down an pivot pins an bolt catches. Update the rifles as they come in or during inventory. Seeing those old bolts an bolt carriers makes me think those rifles never get the yearly depo (higher level) inspection. Using a 1965 bolt group in a 2000-isn A2 barrel for a go gun.

MWO is Modification Work Order, Annual inspections and gaging are done by Direct Support under the old maintenance system which is now known as Field Maintenance under the new system. Depending on the recoverability code, demil code or controlled item inventory code determines what you can throw in the trash, have to mutiliate or, turn into to DRMO for demilitarization. Anymore, unless it is a pin, spring or screw, you have to turn in the unserviceable (old) part to clear the new part in the supply system.

Wpns Man

Supply Daddie called it a mandatory work order. A1 parts, E barrels, black follower mags and others pulled an replaced. Heck, 90% of the arms room was F coded before deployment. The reason was lack of annual inspections an zero TM's. Learned you needed the disks an TM. Big Army took everything an issued new toys for the sand box (2004). The Unit was National Guard so pre 9/11 many Units had shit for funding an States didn't care.

Posted: 2/18/2017 9:15:18 PM EDT

[#19]

How about one with a number four on it?

Posted: 2/18/2017 10:24:51 PM EDT

[#20]

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Quoted:
How about one with a number four on it?

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They used an electric pencil to change A1 to A2, never seen that. Over stamps or mill an restamp was the norm.

Posted: 2/18/2017 10:28:26 PM EDT

[#21]

Quote History

Quoted:
My take on them from a manufacturing stand point is that the serrations on the transitional stops were vestigial.
The original bolt stops just had the serrated lower. When the change to the bumped up lower end came thru they just went back in the mold and added that detail.
It was a subtractive operation in that they removed metal from the mold to add the bump. Then when the molds wore out and new ones were made the serrated detail was left off of the new molds.

View Quote

I'm going with this.