Alllen Bundy
Member
Continuing from:
My Journey From Sig P365 to P365X and Modifications Beyond
(https://www.thehighroad.org/index.p...nd-modifications-beyond.891955/#post-11996270)
P365/X/XL/SAS Grip Module Modifications
(https://www.thehighroad.org/index.php?threads/p365-x-xl-sas-grip-module-modifications.892045/)
Extending the magazine release button Sig P365/X/XL/SAS
(https://www.thehighroad.org/index.p...zine-release-button-sig-p365-x-xl-sas.892113/)
Weighting the P365/X/XL/SAS Grip Module.
(https://www.thehighroad.org/index.php?threads/weighting-the-p365-x-xl-sas-grip-module.892243/)
Polishing the Stripper Rail - Sig P365/X/XL/SAS
(https://www.thehighroad.org/index.php?threads/polishing-the-stripper-rail-sig-p365-x-xl-sas.892413/P
Recoil Spring Assemblies, Sig vs Rival Arms/ISMI for P365/X/SAS
(https://www.thehighroad.org/index.p...sig-vs-rival-arms-ismi-for-p365-x-sas.892594/)
Failure to Return To Battery Prevention
There have been reports of the Sig P365/X/XL/SAS failing to return the slide to battery, especially when new. This is caused by excessive friction from multiple sources that can add up to cause a RTB failure. With the chamber loaded, you should be able to pull the slide slightly out of battery and the recoil spring should be able to pull the slide closed. But this is often not the case, especially with a brand new P365/X/XL/SAS.
These friction sources are:
The roughness of the left adjacent wall to the breech face.
The roughness of the breech face.
The sharp edge of the extractor claw and roughness underneath the extractor claw.
Excessive spring force on the extractor claw.
Burned powder residue on:
The left adjacent wall to the breech face.
The breech face.
The underside of the extractor claw.
------------
Some of the rough areas will eventually be polished by many thousands of rounds being fired. But I really don't want to wait that long or spend that much money on ammunition just to have my pistol working reliably and at peak performance.
A bit of polishing to the breech face, the left adjacent wall to the breech face, and the extractor claw can significantly reduce friction that can impede the slide returning to battery. It's best to remove the extractor for better access to polish these parts. Not to mention that while you have the extractor removed it's a great time to clean and re-lube it, as well as inspect everything for potential problems.
The hole in the slide for the spring pin that holds the extractor in place is about 0.0925" in diameter. A 3/32" (0.09375") drift punch may be a wee bit too large in diameter unless it is a bit undersized. You could probably sand down the diameter of a 3/32" drift punch just a wee bit to fit. Make sure that the end of your drift punch doesn't have any burrs or sharp edges on it. If you don't have the proper size drift punch you can get by using the butt end of a #43 drill bit, which is about 0.089" in diameter. Just make sure that the bottom edge of the drill bit is deburred, and also make sure to hone off any protruding size or text markings on the side of the drill bit. It doesn't require very much force to tap out the spring pin holding the extractor in place. The videos referenced at the end will show you how.
Also note that some people recommend replacing the spring pin with a new one every time. I think that this is partly due to wear on the spring pin, but also because some people are not very careful and they bugger up the end of the spring pin when they insert it. The end of the spring pin can also be buggered from the factory, as mine was. The spring pin made by rolling up a thin sheet of spring material. The end of the spring coil will have an edge on it that you want to face towards the outside, so that the extractor only rides on the rounded surface of the spring pin.
Roughness of the left adjacent wall to the breech face causes excessive friction in opposition to the shell case sliding underneath the extractor, preventing the slide from returning to battery (Closed Slide). The left adjacent wall to the breech face was actually rough enough that it ground brass off the side of the shell cases. Wet sand (600 grit sandpaper followed by 1,000 grit) the left adjacent wall to the breech face, just enough to smooth out the rough spots. A rectangular bar of the right size would aid in maintaining a flat surface as well as keeping it perpendicular to the breech face. Cut thin strips of sandpaper and wrap them lengthwise around the bar. You don't need to sand out every scratch to eliminate most of the friction.
I used a popsicle stick. I cut the rounded end off and then I wrapped a sandpaper strip the long way around the popsicle stick. But the wood tends to swell and popsicle sticks aren't always as flat as they could be. The next time that I do this I will take the time to make an aluminum bar just the right size to aid in the sanding.
To monitor the progress of the sanding, I would occasionally cover the area that I was sanding with a Sharpie marker and then lightly sand over it to see any low spots.
Another source of friction is the roughness of the breech face. The roughness impedes the sliding of the rear of the shell case against the breech face while the shell case is trying to align itself with the firing chamber. An unpolished breech face requires about a 7.5% higher force to chamber a round, than a polished breech face, when using a stock Sig Magazine. And by polished I mean that I wet sanded to 1,200 grit and I did NOT sand out all of the grinding marks.
HOWEVER, the MagGuts 12 + 2 magazine spring kit uses an inferior magazine follower design, and the last few rounds are NOT presented at an optimum angle to enter the firing chamber. With the MagGuts magazine kit, it can require more than double the force to chamber a round, compared to the Sig magazine. An unpolished breech face requires about a 22.5% higher force to chamber the last round, than a polished breech face, when using a MagGuts modified Magazine.
For the breech face you want to cut strips of wet or dry sandpaper just barely wide enough to fit with into the width of the breech face. Then wrap the strips of lengthwise around something flat, then carefully wet sand making sure that you are sanding flat against the breech face. Also note that the breech face is ground at two different angles and it does take some skill to sand these surfaces smooth, flat, and maintain both angles. (I should say that MY breech face was ground at two different angles. I'm not sure if this is normal.) I used 600, 800, 1,000, and finally 1,200 grit wet or dry sandpaper. I didn't sand out all of the grinding marks. I just smoothed out the surface a bit.
There also happened to be a small depression in the breech face of my P365 caused by Sig's irregular grinding. But I didn't try to sand out the depression. I'm not sure how much metal can be removed before it starts causing problems, so I didn't try to remove very much of the metal surface. I just sanded enough to smooth it out.
The edge of the extractor claw was also sharp enough to dig into the soft brass shell case. This sharp edge needs to be sanded just smooth enough so that it doesn't dig into the brass of the shell cases. A little bit of wet sanding from 600 grit sandpaper followed by 1,000 grit is all that it takes. Keep in mind that you can only remove about 0.011" of the edge of the extractor claw before it no longer reaches the bottom of the extractor groove in the shell case. I may have sanded about 0.001" off of the edge of the extractor. Also, sanding off the sharp edge of the extractor will have no significant effect on it's lifespan. The sharp edge would normally eventually wear off with use and once the sharp edge was gone, the wear would reduce exponentially.
The underside of the extractor claw was also a bit rough, so I sanded that as well. I'm not sure if it is normal, but my extractor has a depression in the underside the extractor claw. I decided that it might weaken the claw too much if I completely sanded out the depression. So I just sanded over the underside so it made a smooth transition. I'll be buying a spare extractor and report back as to whether or not it also has the same depression.
This polishing won't prevent every failure to return to battery, but it will reduce the possibility. So far the results are good. Since the polishing of the breech face, the left adjacent wall, and the extractor, I've fired a total of 176 rounds, comprised of 6 different brands/models of cartridges. No return to battery problems or other problems occurred.
Other causes of excessive friction are a dirty breech face, dirty extractor, and dirty feed ramp into the firing chamber. The obvious solution is to keep the breech face, extractor, and the barrel clean. 100% reliability isn't very important for a range gun. But for a defensive weapon, I'm going to clean it after every time I shoot it.
I noticed that after 176 rounds were fired at the last range session, a substantial amount of residue had built up on the breech face and it did significantly increase the friction. It would be great if there was a low friction no stick surface that could be applied to the breech face.
Always check the barrel to make sure that there isn't any roughness on the feed ramp. Mine seemed fine and didn't appear to need any attention.
A bandaid fix that some people have been using is to grind the extractor spring shorter. But this is the WRONG way to reduce friction, which may eventually cause failure to extract problems down the road. Reducing the spring pressure on the extractor claw does reduce friction against the shellcase enough to fix some return to battery failures. But instead of grinding the spring shorter, you can safely actuate the extractor claw repeatedly in order to speed up the break-in of the extractor spring. This will reduce friction to some extent and not cause a reliability problem.
I also noticed that when comparing the stock double spring Sig RSA to the single spring Rival Arms/ISMI RSA, the Sig RSA could more easily pull the slide closed under adverse conditions. The Sig dual recoil spring assembly appears to have more spring preload than the Rival Arms/ISMI spring. After a short break-in period, the force required to rack the slide, with either the Sig or the Rival Arms RSA, was about 76 Newtons, which works out to be almost 17 lbs on the nose, which is what the recoil spring force is supposed to be. When both of the RSAs were new the spring force was about 1 lb more. FYI, I removed the disconnector to eliminate any friction that could cause measurement errors.
Some of you may be thinking that you can reduce friction even further by polishing the underside of the slide where it is contacted by the disconnector. The underside of the slide does feel rough. But I would recommend avoiding the temptation to polish it smooth. While this is counter intuitive, polishing through the Nitron surface on the slide may actually INCREASE friction and result in that stick-slip chattering action. You need to keep in mind that the disconnector and the stainless steel of the slide are fairly similar materials. Contact by dissimilar materials usually results in lower friction. At most, you might be able to use ultra fine sandpaper to polish the Nitron finish a little bit. But do NOT sand through the Nitron finish down to the bare stainless steel slide!
Eventually, many of the RTB problems will tend to disappear after you fire enough rounds for the brass shell cases to polish the steel. But that may take 1,000s and 1,000s of rounds and it still may not eliminate all excessive friction problems.
Everything that I've suggested doing is really just the fine finishing work that Sig didn't bother to do. Reducing friction a little bit here and there may add up to make enough difference that it may prevent a RTB failure during a worst case defensive situation. A little bit of elbow grease on your part might prevent a failure when it's critical. It allows for a greater margin of error before things go South.
But it's your decision as to whether or not you have the skills to perform this finishing work, or even think that it is necessary.
I recommend that you watch these videos below before attempting any work on the P365/X/XL/SAS.
Best way to remove a Sig P320 or P365 magazine release button
(www.youtube.com/watch?v=FZYBWC6pCdg)
How to remove new and old style P365 striker assembly
(www.youtube.com/watch?v=83hAANDK-zI)
SIG Sauer P365 COMPLETE disassembly. Part 1 of 2
(www.youtube.com/watch?v=fV4UFjgPx3Q)
SIG Sauer P365 complete reassembly. Part 2 of 2
(www.youtube.com/watch?v=tWZMzN8Nlzs)
Next: Bullet Setback in Sig P365/X/XL/SAS
My Journey From Sig P365 to P365X and Modifications Beyond
(https://www.thehighroad.org/index.p...nd-modifications-beyond.891955/#post-11996270)
P365/X/XL/SAS Grip Module Modifications
(https://www.thehighroad.org/index.php?threads/p365-x-xl-sas-grip-module-modifications.892045/)
Extending the magazine release button Sig P365/X/XL/SAS
(https://www.thehighroad.org/index.p...zine-release-button-sig-p365-x-xl-sas.892113/)
Weighting the P365/X/XL/SAS Grip Module.
(https://www.thehighroad.org/index.php?threads/weighting-the-p365-x-xl-sas-grip-module.892243/)
Polishing the Stripper Rail - Sig P365/X/XL/SAS
(https://www.thehighroad.org/index.php?threads/polishing-the-stripper-rail-sig-p365-x-xl-sas.892413/P
Recoil Spring Assemblies, Sig vs Rival Arms/ISMI for P365/X/SAS
(https://www.thehighroad.org/index.p...sig-vs-rival-arms-ismi-for-p365-x-sas.892594/)
Failure to Return To Battery Prevention
There have been reports of the Sig P365/X/XL/SAS failing to return the slide to battery, especially when new. This is caused by excessive friction from multiple sources that can add up to cause a RTB failure. With the chamber loaded, you should be able to pull the slide slightly out of battery and the recoil spring should be able to pull the slide closed. But this is often not the case, especially with a brand new P365/X/XL/SAS.
These friction sources are:
The roughness of the left adjacent wall to the breech face.
The roughness of the breech face.
The sharp edge of the extractor claw and roughness underneath the extractor claw.
Excessive spring force on the extractor claw.
Burned powder residue on:
The left adjacent wall to the breech face.
The breech face.
The underside of the extractor claw.
------------
Some of the rough areas will eventually be polished by many thousands of rounds being fired. But I really don't want to wait that long or spend that much money on ammunition just to have my pistol working reliably and at peak performance.
A bit of polishing to the breech face, the left adjacent wall to the breech face, and the extractor claw can significantly reduce friction that can impede the slide returning to battery. It's best to remove the extractor for better access to polish these parts. Not to mention that while you have the extractor removed it's a great time to clean and re-lube it, as well as inspect everything for potential problems.
The hole in the slide for the spring pin that holds the extractor in place is about 0.0925" in diameter. A 3/32" (0.09375") drift punch may be a wee bit too large in diameter unless it is a bit undersized. You could probably sand down the diameter of a 3/32" drift punch just a wee bit to fit. Make sure that the end of your drift punch doesn't have any burrs or sharp edges on it. If you don't have the proper size drift punch you can get by using the butt end of a #43 drill bit, which is about 0.089" in diameter. Just make sure that the bottom edge of the drill bit is deburred, and also make sure to hone off any protruding size or text markings on the side of the drill bit. It doesn't require very much force to tap out the spring pin holding the extractor in place. The videos referenced at the end will show you how.
Also note that some people recommend replacing the spring pin with a new one every time. I think that this is partly due to wear on the spring pin, but also because some people are not very careful and they bugger up the end of the spring pin when they insert it. The end of the spring pin can also be buggered from the factory, as mine was. The spring pin made by rolling up a thin sheet of spring material. The end of the spring coil will have an edge on it that you want to face towards the outside, so that the extractor only rides on the rounded surface of the spring pin.
Roughness of the left adjacent wall to the breech face causes excessive friction in opposition to the shell case sliding underneath the extractor, preventing the slide from returning to battery (Closed Slide). The left adjacent wall to the breech face was actually rough enough that it ground brass off the side of the shell cases. Wet sand (600 grit sandpaper followed by 1,000 grit) the left adjacent wall to the breech face, just enough to smooth out the rough spots. A rectangular bar of the right size would aid in maintaining a flat surface as well as keeping it perpendicular to the breech face. Cut thin strips of sandpaper and wrap them lengthwise around the bar. You don't need to sand out every scratch to eliminate most of the friction.
I used a popsicle stick. I cut the rounded end off and then I wrapped a sandpaper strip the long way around the popsicle stick. But the wood tends to swell and popsicle sticks aren't always as flat as they could be. The next time that I do this I will take the time to make an aluminum bar just the right size to aid in the sanding.
To monitor the progress of the sanding, I would occasionally cover the area that I was sanding with a Sharpie marker and then lightly sand over it to see any low spots.
Another source of friction is the roughness of the breech face. The roughness impedes the sliding of the rear of the shell case against the breech face while the shell case is trying to align itself with the firing chamber. An unpolished breech face requires about a 7.5% higher force to chamber a round, than a polished breech face, when using a stock Sig Magazine. And by polished I mean that I wet sanded to 1,200 grit and I did NOT sand out all of the grinding marks.
HOWEVER, the MagGuts 12 + 2 magazine spring kit uses an inferior magazine follower design, and the last few rounds are NOT presented at an optimum angle to enter the firing chamber. With the MagGuts magazine kit, it can require more than double the force to chamber a round, compared to the Sig magazine. An unpolished breech face requires about a 22.5% higher force to chamber the last round, than a polished breech face, when using a MagGuts modified Magazine.
For the breech face you want to cut strips of wet or dry sandpaper just barely wide enough to fit with into the width of the breech face. Then wrap the strips of lengthwise around something flat, then carefully wet sand making sure that you are sanding flat against the breech face. Also note that the breech face is ground at two different angles and it does take some skill to sand these surfaces smooth, flat, and maintain both angles. (I should say that MY breech face was ground at two different angles. I'm not sure if this is normal.) I used 600, 800, 1,000, and finally 1,200 grit wet or dry sandpaper. I didn't sand out all of the grinding marks. I just smoothed out the surface a bit.
There also happened to be a small depression in the breech face of my P365 caused by Sig's irregular grinding. But I didn't try to sand out the depression. I'm not sure how much metal can be removed before it starts causing problems, so I didn't try to remove very much of the metal surface. I just sanded enough to smooth it out.
The edge of the extractor claw was also sharp enough to dig into the soft brass shell case. This sharp edge needs to be sanded just smooth enough so that it doesn't dig into the brass of the shell cases. A little bit of wet sanding from 600 grit sandpaper followed by 1,000 grit is all that it takes. Keep in mind that you can only remove about 0.011" of the edge of the extractor claw before it no longer reaches the bottom of the extractor groove in the shell case. I may have sanded about 0.001" off of the edge of the extractor. Also, sanding off the sharp edge of the extractor will have no significant effect on it's lifespan. The sharp edge would normally eventually wear off with use and once the sharp edge was gone, the wear would reduce exponentially.
The underside of the extractor claw was also a bit rough, so I sanded that as well. I'm not sure if it is normal, but my extractor has a depression in the underside the extractor claw. I decided that it might weaken the claw too much if I completely sanded out the depression. So I just sanded over the underside so it made a smooth transition. I'll be buying a spare extractor and report back as to whether or not it also has the same depression.
This polishing won't prevent every failure to return to battery, but it will reduce the possibility. So far the results are good. Since the polishing of the breech face, the left adjacent wall, and the extractor, I've fired a total of 176 rounds, comprised of 6 different brands/models of cartridges. No return to battery problems or other problems occurred.
Other causes of excessive friction are a dirty breech face, dirty extractor, and dirty feed ramp into the firing chamber. The obvious solution is to keep the breech face, extractor, and the barrel clean. 100% reliability isn't very important for a range gun. But for a defensive weapon, I'm going to clean it after every time I shoot it.
I noticed that after 176 rounds were fired at the last range session, a substantial amount of residue had built up on the breech face and it did significantly increase the friction. It would be great if there was a low friction no stick surface that could be applied to the breech face.
Always check the barrel to make sure that there isn't any roughness on the feed ramp. Mine seemed fine and didn't appear to need any attention.
A bandaid fix that some people have been using is to grind the extractor spring shorter. But this is the WRONG way to reduce friction, which may eventually cause failure to extract problems down the road. Reducing the spring pressure on the extractor claw does reduce friction against the shellcase enough to fix some return to battery failures. But instead of grinding the spring shorter, you can safely actuate the extractor claw repeatedly in order to speed up the break-in of the extractor spring. This will reduce friction to some extent and not cause a reliability problem.
I also noticed that when comparing the stock double spring Sig RSA to the single spring Rival Arms/ISMI RSA, the Sig RSA could more easily pull the slide closed under adverse conditions. The Sig dual recoil spring assembly appears to have more spring preload than the Rival Arms/ISMI spring. After a short break-in period, the force required to rack the slide, with either the Sig or the Rival Arms RSA, was about 76 Newtons, which works out to be almost 17 lbs on the nose, which is what the recoil spring force is supposed to be. When both of the RSAs were new the spring force was about 1 lb more. FYI, I removed the disconnector to eliminate any friction that could cause measurement errors.
Some of you may be thinking that you can reduce friction even further by polishing the underside of the slide where it is contacted by the disconnector. The underside of the slide does feel rough. But I would recommend avoiding the temptation to polish it smooth. While this is counter intuitive, polishing through the Nitron surface on the slide may actually INCREASE friction and result in that stick-slip chattering action. You need to keep in mind that the disconnector and the stainless steel of the slide are fairly similar materials. Contact by dissimilar materials usually results in lower friction. At most, you might be able to use ultra fine sandpaper to polish the Nitron finish a little bit. But do NOT sand through the Nitron finish down to the bare stainless steel slide!
Eventually, many of the RTB problems will tend to disappear after you fire enough rounds for the brass shell cases to polish the steel. But that may take 1,000s and 1,000s of rounds and it still may not eliminate all excessive friction problems.
Everything that I've suggested doing is really just the fine finishing work that Sig didn't bother to do. Reducing friction a little bit here and there may add up to make enough difference that it may prevent a RTB failure during a worst case defensive situation. A little bit of elbow grease on your part might prevent a failure when it's critical. It allows for a greater margin of error before things go South.
But it's your decision as to whether or not you have the skills to perform this finishing work, or even think that it is necessary.
I recommend that you watch these videos below before attempting any work on the P365/X/XL/SAS.
Best way to remove a Sig P320 or P365 magazine release button
(www.youtube.com/watch?v=FZYBWC6pCdg)
How to remove new and old style P365 striker assembly
(www.youtube.com/watch?v=83hAANDK-zI)
SIG Sauer P365 COMPLETE disassembly. Part 1 of 2
(www.youtube.com/watch?v=fV4UFjgPx3Q)
SIG Sauer P365 complete reassembly. Part 2 of 2
(www.youtube.com/watch?v=tWZMzN8Nlzs)
Next: Bullet Setback in Sig P365/X/XL/SAS
Last edited:
