SoCalDep
04-10-2020, 11:05 PM
My department recently authorized the use of pistol-mounted optics and so far we have over sixty people who have completed the prerequisites and two-day class. By far the biggest failure we’ve seen involves stripping hex screw heads or shearing the screws. A small bit of background:
We authorize factory-configured optic-capable pistols (M&P CORE, Glock MOS, STI Duo, etc.) and the authorized optics at this time are the RMR type 2, Aimpoint ACRO P-1, and Sig Romeo1 Pro. No aftermarket slides and no direct milling. I’m personally a fan of direct milling but the supervisors could not be convinced. Hopefully one day.
In our training/use we’ve seen a few sheared factory screws (two on Glock MOSs and a couple on M&P Cores) and a few stripped hex heads.
So far I’ve been very successful with my work and training pistols, which include three M&P COREs with RMRs and an SRO, and a Glock 19MOS with an RMR. I have a Unity Tactical ATOM slide and that’s where this all started. The ATOM RMR plate takes a 5-40 x 3/8” screw which is too long for the Holosun 507C I borrowed and mounted on it as a loaner for a class. I ended up shortening the screws and it worked great for around 1,100 rounds in the class. I purchased a Holosun 508T and when mounting it one of the screw’s hex-heads stripped. I could probably run it as is but that screw really bugs me so I’m looking at replacements. Currently I am waiting the California COVID 10-day to whenever they get to it waiting period for a new Glock 45 and have an ACRO en route. I already picked up a Tango Down mount and I expect no issues with the included McMaster-Carr screws, but I also took advice from Wayne Dobbs that the McMaster-Carr screws are superior to factory, so I did a bunch of research and this is what I’ve found:
Mr. Dobbs recommends the McMaster-Carr M3x0.5 x 6mm screws (part # 94414A712) for the Aimpoint factory Glock MOS mount. These are the same dimensions as the factory MOS plate-to-slide screws for the MOS plates. The screws for the MOS cover plate (no optic) seem to be M3x0.5 x 8mm.
I looked into the Google black hole as well as C&H, Forward Control Design, and Battlewerx, and found more dimensions and screw lengths for different handguns and optics. Battlewerx does a great job of listing dimensions and at least based on their pictures seem to use YFS screws. They do seem to be a really great “easy-button” option for replacement screws, but I’m looking for a source where I can get a larger number to have on hand for students who have issues. I also want Torx heads not hex.
McMaster-Carr offers flat head Torx screws in stainless steel, alloy steel, and high-strength 18-8 stainless. The alloy steel seems the “strongest” so that’s what I’m thinking of ordering, but I have questions because I’m not an expert on metallurgy, screws, etc.
First, the dimensions I found for the various optic/pistol configurations:
6-32 x 3/8” - RMR to MOS plate
6-32 x 5/16” - Holosun 407/507/508C and T series to MOS plate (Not available from McMaster)
M4x0.7 x 15.8mm - DeltaPoint Pro to MOS plate
6-32 x 1/2” - RMR or Holosun to M&P CORE
5-40 x 5/16” - Holosun 508T and others to Unity ATOM (Not available - I’ll grind down 3/8” ones)
It seems the FCD OPF-G plate is the same as the Glock MOS, using the same screw dimensions for the RMR.
From other threads, the C&H plate does not work with either the Trijicon “Glock sealing plate kit” screws or the factory Trijicon RMR screws but the Battlewerx screws fit. I have no personal experience with that.
Now the questions:
I want to order McMaster-Carr screws in the above dimensions since they use Torx heads (actually Torx plus which must be better because it says “plus”) and they seem to meet “standards” whatever they are.
Since I’m ignorant to all the dimensional aspects of these McMaster screws (82 degree counter-sink angle, thread count, pitch, course thread, etc.), does anyone know if ordering them would work to replace the factory screws or is there the potential for them to not fit?
The high-strength stainless is WAY more expensive than the alloy steel, which is listed as having comparable strength. I’d like to have a large backstock, so I like the bulk price of the alloy steel but if it is significantly sub-par the the high-strength stainless I’ll go with the stainless since it’s kinda important.
Lastly, I’m operating on the assumption that these screws are better than the factory screws supplied with most optics - If this is not the case I’d rather bite the bullet for quality and get the screws straight from the optic or pistol manufacturer, but it seems to me that for many of them they are cheaper parts with very high markups. What do you all think of the quality of McMaster-Carr screws and would they be an “upgrade”?
I know there are all sorts of other aspects of installation to include thread-lock, torque specs, thread seal or torque seal, etc., but those are primarily dealt with in other threads so I figured I’d focus on the screws themselves here. I still need to research the Sig Romeo1 Pro and the P365XL/Romeo Zero, as well as some other optics we’re looking at testing, but I’m calling this a good start.
Any help or information would be greatly appreciated!
We authorize factory-configured optic-capable pistols (M&P CORE, Glock MOS, STI Duo, etc.) and the authorized optics at this time are the RMR type 2, Aimpoint ACRO P-1, and Sig Romeo1 Pro. No aftermarket slides and no direct milling. I’m personally a fan of direct milling but the supervisors could not be convinced. Hopefully one day.
In our training/use we’ve seen a few sheared factory screws (two on Glock MOSs and a couple on M&P Cores) and a few stripped hex heads.
So far I’ve been very successful with my work and training pistols, which include three M&P COREs with RMRs and an SRO, and a Glock 19MOS with an RMR. I have a Unity Tactical ATOM slide and that’s where this all started. The ATOM RMR plate takes a 5-40 x 3/8” screw which is too long for the Holosun 507C I borrowed and mounted on it as a loaner for a class. I ended up shortening the screws and it worked great for around 1,100 rounds in the class. I purchased a Holosun 508T and when mounting it one of the screw’s hex-heads stripped. I could probably run it as is but that screw really bugs me so I’m looking at replacements. Currently I am waiting the California COVID 10-day to whenever they get to it waiting period for a new Glock 45 and have an ACRO en route. I already picked up a Tango Down mount and I expect no issues with the included McMaster-Carr screws, but I also took advice from Wayne Dobbs that the McMaster-Carr screws are superior to factory, so I did a bunch of research and this is what I’ve found:
Mr. Dobbs recommends the McMaster-Carr M3x0.5 x 6mm screws (part # 94414A712) for the Aimpoint factory Glock MOS mount. These are the same dimensions as the factory MOS plate-to-slide screws for the MOS plates. The screws for the MOS cover plate (no optic) seem to be M3x0.5 x 8mm.
I looked into the Google black hole as well as C&H, Forward Control Design, and Battlewerx, and found more dimensions and screw lengths for different handguns and optics. Battlewerx does a great job of listing dimensions and at least based on their pictures seem to use YFS screws. They do seem to be a really great “easy-button” option for replacement screws, but I’m looking for a source where I can get a larger number to have on hand for students who have issues. I also want Torx heads not hex.
McMaster-Carr offers flat head Torx screws in stainless steel, alloy steel, and high-strength 18-8 stainless. The alloy steel seems the “strongest” so that’s what I’m thinking of ordering, but I have questions because I’m not an expert on metallurgy, screws, etc.
First, the dimensions I found for the various optic/pistol configurations:
6-32 x 3/8” - RMR to MOS plate
6-32 x 5/16” - Holosun 407/507/508C and T series to MOS plate (Not available from McMaster)
M4x0.7 x 15.8mm - DeltaPoint Pro to MOS plate
6-32 x 1/2” - RMR or Holosun to M&P CORE
5-40 x 5/16” - Holosun 508T and others to Unity ATOM (Not available - I’ll grind down 3/8” ones)
It seems the FCD OPF-G plate is the same as the Glock MOS, using the same screw dimensions for the RMR.
From other threads, the C&H plate does not work with either the Trijicon “Glock sealing plate kit” screws or the factory Trijicon RMR screws but the Battlewerx screws fit. I have no personal experience with that.
Now the questions:
I want to order McMaster-Carr screws in the above dimensions since they use Torx heads (actually Torx plus which must be better because it says “plus”) and they seem to meet “standards” whatever they are.
Since I’m ignorant to all the dimensional aspects of these McMaster screws (82 degree counter-sink angle, thread count, pitch, course thread, etc.), does anyone know if ordering them would work to replace the factory screws or is there the potential for them to not fit?
The high-strength stainless is WAY more expensive than the alloy steel, which is listed as having comparable strength. I’d like to have a large backstock, so I like the bulk price of the alloy steel but if it is significantly sub-par the the high-strength stainless I’ll go with the stainless since it’s kinda important.
Lastly, I’m operating on the assumption that these screws are better than the factory screws supplied with most optics - If this is not the case I’d rather bite the bullet for quality and get the screws straight from the optic or pistol manufacturer, but it seems to me that for many of them they are cheaper parts with very high markups. What do you all think of the quality of McMaster-Carr screws and would they be an “upgrade”?
I know there are all sorts of other aspects of installation to include thread-lock, torque specs, thread seal or torque seal, etc., but those are primarily dealt with in other threads so I figured I’d focus on the screws themselves here. I still need to research the Sig Romeo1 Pro and the P365XL/Romeo Zero, as well as some other optics we’re looking at testing, but I’m calling this a good start.
Any help or information would be greatly appreciated!