Thank you for the very kind explanation. I appreciate your perspective more than you know. I started out hang gliding, moved into ultralight flying, then to experimental and classic airplanes and then on to general aviation aircraft. Along the way there were several people we met who made mistakes and got themselves and others hurt or killed and caused regulators and legislators to want to further restrict the activities of the rest of us.
We have dozens of mostly vintage firearms. I have never had a dangerous malfunction, but I do not trust any gun not to blow up in my face. I am very systematic and have redundant checks with every cartridge I reload that has enough case capacity to inadvertently double charge. I don’t trust myself a great deal more than I trust a 75 or 100 year old gun.
Your warnings to those who might trust a gun made from unsatisfactory materials and designed by someone who is not a gunsmith or knowledgeable of ballistics are good reminders to everyone here. That goes also for components like homemade lower receivers which might or might not be up to the task depending on the skill and knowledge of the person who made the part.
I know that there have been failures of re-welded receivers made up from “de-militarized” pieces that have caused injuries in the past. That is kind of the 1950s and 1960s equivalent to these 80% receiver kits available today. I have a Golden State Arms BM59 chambered to .308 that has a WWII surplus Garand receiver that was “remanufactured” from an original that was cut in half. It has never given me any difficulties but I keep a very close eye on that receiver. As should anyone with a homemade lower used in a AR type of rifle.
” ... I know that there have been failures of re-welded receivers made up from “de-militarized” pieces that have caused injuries in the past. That is kind of the 1950s and 1960s equivalent to these 80% receiver kits available today. I have a Golden State Arms BM59 chambered to .308 that has a WWII surplus Garand receiver that was “remanufactured” from an original that was cut in half. It has never given me any difficulties but I keep a very close eye on that receiver. ... “
If the news weren’t already bad enough, I fear I’m going to convey more. fireman15 won’t like it much.
Please don’t fire ammunition labeled “308 Winchester” in any Garand-type rifle marked “7.62 NATO,” nor in any rifle marked “7.62 NATO.” They aren’t the same.
Rewelded US M1 Garand receivers are not “equivalent” to modern-day AR-15 style lower receivers manufactured to 80 percent completion and finished up by the consumer.
Every test performed on rewelded receivers has found that dimensions and metal hardness levels do not meet US DoD MIL STD for the weapon systems in question. The technical understanding, skill, experience level, and savvy of those doing the “remanufacture” are irrelevant: the chief constraint lies in the metallurgy of the steel alloys originally used in receiver manufacture.
Once forged, tempered and finished, those steels resisted wear and deformation quite well, but when rewelded, could not be returned to original strength and hardness specifications. Safety criteria are thus in doubt; it does not matter how carefully, how closely the rewelded receivers are machined. None among those measured have been found to meet DoD dimensional standards.
Many users assume that if the headspace is within limits, all is safe. This is a misconception also.
Generally speaking, there is a small window of variation inside of which headspace can be considered safe; for the US 30-06 cartridge, it’s about the thickness of a sheet of copier paper. Too small, and the rifle (especially an autoloader like the US M1 Garand) runs the risk of premature ignition - before the bolt is fully locked. Too large, and the cartridge case cannot stretch enough to seal in the gases without rupturing. Catastrophic failure and serious injury or death can happen.
The headspace of any rifle can be easily and quickly checked with precision-manufactured gauges, sold by Brownells and other toolmakers. They are labeled GO and NO GO; if the bolt - suitably prepped - closes on the GO gauge, headspace is long enough. If it closes on the NO GO gauge, headspace is too long.
A related problem arises with the use of an extra-long gauge called the FIELD gauge. This one is a slight amount larger than the NO GO gauge and was developed by the War Dept (pre DoD) for emergency use. US Army Ordnance procedure was to check rifles using the GO and NO GO gauges; any rifle failing inspection was tagged for adjustment and proper repair. That was OK for routine (non-combat) activities, but if the rifles were being inspected in field circumstances and might be urgently required in action, it was found they could still function, though with some higher risk level, deemed acceptable.
The catch: those risk levels stayed inside acceptable limits only if MIL STD ammunition was being fired, and the rifle passed every other gauge check. The rifles failing NO GO but passing FIELD headspace checks were tagged and removed from service at the earliest safe opportunity.
Rifles failing the FIELD check were removed from service on the spot.
US shooters, penny-pinchers that they are, very often assume they are in safe territory firing any loads they please in their FIELD-passing rifle. This is not the case; no civilian factory loads match military ammunition dimensions exactly. The metallurgy of primers, cases, bullets are different (different hardness means different coefficients of friction and different primer sensitivity, hence different pressures), and loads today are often much higher in velocity. If different propellants are used, chamber pressure results will be different even at the same velocities.
Reloads introduce another variable with even poorer control. Rifles passing the FIELD check but failing the NO GO check were to be fired only with new MIL STD cartridges; reloads were never considered.
Many shooters assume that if their M1’s headspace safely passes the GO check, they are OK. But there is more to safe operation.
The Garand design does not have a firing pin return spring. To reduce the chances of the firing pin slamming forward, igniting the primer before the hammer was released, or before the bolt was fully locked, a cam surface (safety cam) was machined into the receiver bridge, behind and below the bolt retraction space. This cam checked forward movement of the firing pin until the bolt turned into its locked position.
Bolts, firing pins, and receivers stretch and wear. If the M1’s safety cam in its receiver bridge is worn or battered beyond limits, the firing pin can hit the primer and set it off. True of BM-59, M14, or M1 Carbine type rifles as well.
In routine use, military ordnance personnel checked all these functions and dimensions when rifles were turned in for maintenance, and corrected any that did not meet standards, or removed the rifle from service and sent it to higher echelons for further repair.
The primary risk today for users of rewelded Garand-type receivers is that the receiver bridge is behind the reweld location, while the bolt’s locking lug seats are ahead of it. Thus, a rewelded rifle can have a new barrel perfectly installed to minimum dimensions, the headspace can gauge to a safe size, and an unworn safety cam; but the safety cam can be out of position because of the reweld, thus beyond specification. Safety, dimension, and functional checks performed by the average repair technician will not detect the problem.
I apologize to the forum for wordiness, but the risks to shooter safety are too great to avoid describing the situation.
I have performed the unhappy task of telling a number of owners of several very nice-looking US M1 Garand rifles that their headspace was beyond safe limits, that their receivers had been rewelded, that their firing pin safety cams were worn beyond safe limits, or that their hardware was otherwise risky. The expressions of disappointment that clouded their features on hearing such words made for a very disagreeable experience. But to me, as a minor toiler in the industry, it was worth any amount of abuse, crossness, and bad language in my ears, to avoid injury to shooters.
Same goes for freepers who shoot these rifles, though I haven’t met any personally.
All shooters and owners of Garand-type rifles (especially the BM-59-style conversions and other such configurations never subjected to determination of safe dimensions and acceptable wear tolerance) are thus urged to get their rifles checked for headspace, firing pin protrusion, safety cam action, and a number of other critical safety aspect. This includes M1 Carbines. The youngest of these receivers is over 60 years old, and all of them have been out of the control of DoD for decades, during which few records of use, wear, maintenance, or storage have been kept. Despite Americans’ belief that “they don’t make em like they used to,” these rifles cannot last forever.
Users interested in safe operation and repair should consult the technical manuals written by Jerry Kuhnhausen (sold by Brownells, last I checked), or a trustworthy provider of parts and repair services like Fulton Armory. Such work can be costly, but isn’t terribly high, compared to coping with a catastrophic failure, or injuries, or death.
” ... I know that there have been failures of re-welded receivers made up from “de-militarized” pieces that have caused injuries in the past. That is kind of the 1950s and 1960s equivalent to these 80% receiver kits available today. I have a Golden State Arms BM59 chambered to .308 that has a WWII surplus Garand receiver that was “remanufactured” from an original that was cut in half. It has never given me any difficulties but I keep a very close eye on that receiver. ... “
If the news weren’t already bad enough, I fear I’m going to convey more. fireman15 won’t like it much.
Please don’t fire ammunition labeled “308 Winchester” in any Garand-type rifle marked “7.62 NATO,” nor in any rifle marked “7.62 NATO.” They aren’t the same.
Rewelded US M1 Garand receivers are not “equivalent” to modern-day AR-15 style lower receivers manufactured to 80 percent completion and finished up by the consumer.
Every test performed on rewelded receivers has found that dimensions and metal hardness levels do not meet US DoD MIL STD for the weapon systems in question. The technical understanding, skill, experience level, and savvy of those doing the “remanufacture” are irrelevant: the chief constraint lies in the metallurgy of the steel alloys originally used in receiver manufacture.
Once forged, tempered and finished, those steels resisted wear and deformation quite well, but when rewelded, could not be returned to original strength and hardness specifications. Safety criteria are thus in doubt; it does not matter how carefully, how closely the rewelded receivers are machined. None among those measured have been found to meet DoD dimensional standards.
Many users assume that if the headspace is within limits, all is safe. This is a misconception also.
Generally speaking, there is a small window of variation inside of which headspace can be considered safe; for the US 30-06 cartridge, it’s about the thickness of a sheet of copier paper. Too small, and the rifle (especially an autoloader like the US M1 Garand) runs the risk of premature ignition - before the bolt is fully locked. Too large, and the cartridge case cannot stretch enough to seal in the gases without rupturing. Catastrophic failure and serious injury or death can happen.
The headspace of any rifle can be easily and quickly checked with precision-manufactured gauges, sold by Brownells and other toolmakers. They are labeled GO and NO GO; if the bolt - suitably prepped - closes on the GO gauge, headspace is long enough. If it closes on the NO GO gauge, headspace is too long.
A related problem arises with the use of an extra-long gauge called the FIELD gauge. This one is a slight amount larger than the NO GO gauge and was developed by the War Dept (pre DoD) for emergency use. US Army Ordnance procedure was to check rifles using the GO and NO GO gauges; any rifle failing inspection was tagged for adjustment and proper repair. That was OK for routine (non-combat) activities, but if the rifles were being inspected in field circumstances and might be urgently required in action, it was found they could still function, though with some higher risk level, deemed acceptable.
The catch: those risk levels stayed inside acceptable limits only if MIL STD ammunition was being fired, and the rifle passed every other gauge check. The rifles failing NO GO but passing FIELD headspace checks were tagged and removed from service at the earliest safe opportunity.
Rifles failing the FIELD check were removed from service on the spot.
US shooters, penny-pinchers that they are, very often assume they are in safe territory firing any loads they please in their FIELD-passing rifle. This is not the case; no civilian factory loads match military ammunition dimensions exactly. The metallurgy of primers, cases, bullets are different (different hardness means different coefficients of friction and different primer sensitivity, hence different pressures), and loads today are often much higher in velocity. If different propellants are used, chamber pressure results will be different even at the same velocities.
Reloads introduce another variable with even poorer control. Rifles passing the FIELD check but failing the NO GO check were to be fired only with new MIL STD cartridges; reloads were never considered.
Many shooters assume that if their M1’s headspace safely passes the GO check, they are OK. But there is more to safe operation.
The Garand design does not have a firing pin return spring. To reduce the chances of the firing pin slamming forward, igniting the primer before the hammer was released, or before the bolt was fully locked, a cam surface (safety cam) was machined into the receiver bridge, behind and below the bolt retraction space. This cam checked forward movement of the firing pin until the bolt turned into its locked position.
Bolts, firing pins, and receivers stretch and wear. If the M1’s safety cam in its receiver bridge is worn or battered beyond limits, the firing pin can hit the primer and set it off. True of BM-59, M14, or M1 Carbine type rifles as well.
In routine use, military ordnance personnel checked all these functions and dimensions when rifles were turned in for maintenance, and corrected any that did not meet standards, or removed the rifle from service and sent it to higher echelons for further repair.
The primary risk today for users of rewelded Garand-type receivers is that the receiver bridge is behind the reweld location, while the bolt’s locking lug seats are ahead of it. Thus, a rewelded rifle can have a new barrel perfectly installed to minimum dimensions, the headspace can gauge to a safe size, and an unworn safety cam; but the safety cam can be out of position because of the reweld, thus beyond specification. Safety, dimension, and functional checks performed by the average repair technician will not detect the problem.
I apologize to the forum for wordiness, but the risks to shooter safety are too great to avoid describing the situation.
I have performed the unhappy task of telling a number of owners of several very nice-looking US M1 Garand rifles that their headspace was beyond safe limits, that their receivers had been rewelded, that their firing pin safety cams were worn beyond safe limits, or that their hardware was otherwise risky. The expressions of disappointment that clouded their features on hearing such words made for a very disagreeable experience. But to me, as a minor toiler in the industry, it was worth any amount of abuse, crossness, and bad language in my ears, to avoid injury to shooters.
Same goes for freepers who shoot these rifles, though I haven’t met any personally.
All shooters and owners of Garand-type rifles (especially the BM-59-style conversions and other such configurations never subjected to determination of safe dimensions and acceptable wear tolerance) are thus urged to get their rifles checked for headspace, firing pin protrusion, safety cam action, and a number of other critical safety aspect. This includes M1 Carbines. The youngest of these receivers is over 60 years old, and all of them have been out of the control of DoD for decades, during which few records of use, wear, maintenance, or storage have been kept. Despite Americans’ belief that “they don’t make em like they used to,” these rifles cannot last forever.
Users interested in safe operation and repair should consult the technical manuals written by Jerry Kuhnhausen (sold by Brownells, last I checked), or a trustworthy provider of parts and repair services like Fulton Armory. Such work can be costly, but isn’t terribly high, compared to coping with a catastrophic failure, or injuries, or death.