(too long, won't read: We should be using 18 lb recoil springs with flat bottom firing pin stops and 25 lb mainsprings in our 10mm 1911's)
This probably belongs in the gunsmithing section, but for broader reach I am posting in general discussion. We will move this in a few days.
The conventional wisdom is that we should amp up the recoil spring in our 1911's to reduce frame battering when the slide reaches it's full rearward travel. The idea is the extra power recoil spring will slow down the slide, reducing the impact velocity, and saving undue wear on the frame slide.
A few weeks back, Yondering made a post here about recoil springs not impacting unlock timing in 1911's at all, which got me thinking and reading more. In addition, I am in the midst of a 10mm P12 conversion, which also has me researching.
Those of you who are serious 1911 guys have probably heard of 1911Tuner. You see him at a number of websites, most notably The High Road and m1911.org. He is a literal encyclopedia of 1911 knowledge, especially when it comes to exactly how the gun works and wears out. I have spent a fair bit of time in the evenings over the last few days/weeks reading any and every post I can find at m1911.org where he talks about the 10mm.
He isn't a huge fan of 10mm in the 1911 platform. That isn't to say he hates it either. He is just blunt that the platform was engineered for the standard pressure 45 ACP, not for a cartridge with almost twice the MAP rating. He is straightforward that you will crack slides eventually on a 1911. The are not meant to last forever. And that they will crack faster running 45 ACP +P and faster still with high pressure rounds like 38 super or 10mm. We are still talking a service life of 10,000+ rounds in most cases though, more if you don't run full bore 10mm all the time.
In my reading 1911tuner sites some interesting research done by Ned Christensen of Michiguns. Ned is another serious 1911 guy, making his living tuning and beautifying the platform. Ned did some research many years back on specifically how to tame the 10mm as much as possible in the 1911 platform. His method was to fire a 45 acp 1911 in stock configuration without a recoil spring installed, but with a shock buff in place. After a specified number of rounds the shock buff would be replaced and the test repeated. The shock buffs were then examined and damage detailed. This gave a baseline indicator of the force with which the slide hit the frame.
Ned found that a flat bottom firing pin stop with a 1/16" radius and a 25 lb mainspring resulted in the same approximate damage to the shock buff when firing full power 10mm loads as occured in 45 acp with a stock firing pin stop and mainspring tension.
Based on these findings he recommends the above set-up be coupled with an 18 lb recoil spring, not the heavier 20, 22, and 24 lb springs most of us here are running. Both he and 1911tuner further warn that running heavy recoil springs places undue stress on the slide stop pin and slide stop pin holes in the frame. Stress that they are not designed to handle. Whereas the slide and recoil abutment in the frame were designed to handle the stress if impacts from firing. 1911 tuner has fired literally hundreds of rounds of 45 acp through a commander with no recoil spring just to prove that it will not damage the frame/slide. Please note he did leave the recoil spring plug in place.
Next range outing I am putting the 18 lbs spring back in my Para P16 in place of the 24 lb spring I currently am running. Once the gun passes a 100 round function test with that spring it will be my standard strength based on this information.
I have not linked the articles, as they are many. If you want to read all about it, go to forum.m1911.org/forums.php and run an advanced search for "10mm" and the author 1911tuner.
--Mitch
I'd seen this mentioned in a few places before, but never with an in-depth explanation. Thanks for posting.
Good info...The 1911 is a different action (barrel link) than others like Glocks and S&W's for the way things work and the recoil systems.
Good stuff sqlbullet! I'd read that stuff as well, but it's been a few years so I wasn't able to explain the details well enough in our earlier thread.
One other warning I want to mention is about the 10mm in Para guns - it works, for a while, but is likely to crack the frame and/or slide sooner or later. Been there, done that. Their cast parts just aren't as good for long term durability.
So since my Razorback is stock I should up the mainspring. What's stock?
Stock on a standard Gov't model is 23 lbs. I run a 25 lb with my flat bottom firing pin stop.
quite a few experts on the 1911 platform suggest this with the 10
Internet has allowed me to see much more of the human experience. I've learned a lot about people. For example, once a "fact" gets out, it won't die. Repetition of "facts" can become the basis for their "truth".
Phrases like "batter the frame" and "delay barrel unlocking" are accepted concepts that are completely unsupported by facts.
'tuner' knows 1911's and apparently some physics. A few years ago, I grabbed some paper and a pencil and did some calculations (with reasonable approximations) on the 1911 mechanism. Here's the interpretation of those calculations.
1) "delay barrel unlocking": When the bullet leaves the barrel, the relationship among the slide, barrel and barrel link are independent of the speed of the bullet. At the point where a slow 200gr bullet or a fast 200gr bullet leaves the barrel, the barrel is no more or less likely to be unlocked from the slide.
2) "batter the frame": Recoil springs slow slides by about 22% by time the lower lug hits the recoil abutment. So, the slide is still moving along pretty fast. The frame abutment is designed to handle its job of stopping the slide.
Recoil springs are meant to return the slide to battery. Slowing the slide is a secondary effect. When it comes to using heavier springs, slide speed reduction is to the square root of the spring strength. So, a heavier spring will slow the slide more, but not nearly as much as people seem to imagine. The slide is still moving along. In fact, to reduce the slide speed by half would require a recoil spring so strong, a human could not rack the slide.
The square cut on a 'firing pin stop' alters the shape of the curve of work the slide does as it pushes the hammer back, forcing the slide to transfer more energy into the mainspring at the beginning of the slide's motion.
The 10mm does test the overall 1911 design more. It applies 56% more force on the slide breech face. That's why a well built slide is important. And faster slide movement can challenge magazines to present the next round properly. Personally, that's the only reason I can think of to increase recoil spring rates. The secondary effect of slowing the slide a bit can be used to tweak magazine feed reliability, especially for lighter Commander length slides.
'sqlbullet' thanks for putting that out there.
Not sure how true it is, but I've also read that putting in a stronger recoil spring instead of square bottom firing pin stops and stronger mainspring can cause the slide to spring forward more forcefully and can put additional stress on the locking lugs and the link / link pins.
Quote from: harrygunner on August 01 2012 02:00:41 PM MDT
Internet has allowed me to see much more of the human experience. I've learned a lot about people. For example, once a "fact" gets out, it won't die. Repetition of "facts" can become the basis for their "truth".
Phrases like "batter the frame" and "delay barrel unlocking" are accepted concepts that are completely unsupported by facts.
'tuner' knows 1911's and apparently some physics. A few years ago, I grabbed some paper and a pencil and did some calculations (with reasonable approximations) on the 1911 mechanism. Here's the interpretation of those calculations.
1) "delay barrel unlocking": When the bullet leaves the barrel, the relationship among the slide, barrel and barrel link are independent of the speed of the bullet. At the point where a slow 200gr bullet or a fast 200gr bullet leaves the barrel, the barrel is no more or less likely to be unlocked from the slide.
2) "batter the frame": Recoil springs slow slides by about 22% by time the lower lug hits the recoil abutment. So, the slide is still moving along pretty fast. The frame abutment is designed to handle its job of stopping the slide.
Recoil springs are meant to return the slide to battery. Slowing the slide is a secondary effect. When it comes to using heavier springs, slide speed reduction is to the square root of the spring strength. So, a heavier spring will slow the slide more, but not nearly as much as people seem to imagine. The slide is still moving along. In fact, to reduce the slide speed by half would require a recoil spring so strong, a human could not rack the slide.
The square cut on a 'firing pin stop' alters the shape of the curve of work the slide does as it pushes the hammer back, forcing the slide to transfer more energy into the mainspring at the beginning of the slide's motion.
The 10mm does test the overall 1911 design more. It applies 56% more force on the slide breech face. That's why a well built slide is important. And faster slide movement can challenge magazines to present the next round properly. Personally, that's the only reason I can think of to increase recoil spring rates. The secondary effect of slowing the slide a bit can be used to tweak magazine feed reliability, especially for lighter Commander length slides.
'sqlbullet' thanks for putting that out there.
Excellent read. I personally question everything. Even what I think I know. I'm surprised so many just take this and that for granted. Not that there isn't some plain hard fact out there, but sometimes even then it can depend on certain senarios we don't always realize either. And yeah, chambering 1911s in 10mm Auto doesn't make things any easier either. The 10mm breaks into a lot of new ground other lesser rounds just never gave us reason to put thought into.
23 to 25lb isn't a huge jump. It sounds almost like my Dan Wesson is about perfect right out of the box. Guess I will just wait for the crack to occur. I would like to see some picture evidence when these things happen.
They have pictures in various threads on the m1911.org site. Most are of 45 ACP 1911's that have cracked. It will eventually happen even to them after enough rounds.
Keep in mind, we aren't talking about cracks in the first 1,000 or even 5,000 rounds. We are talking for a 45 about 30,000-50,000 rounds. For a 10mm I would guess 10,000-20,000. The cost of a new slide against the cost of 20,000 rounds of Underwood is nothing.
Maybe a Shock Buffer would do the trick?
Quote from: sqlbullet on August 02 2012 09:55:40 AM MDT
For a 10mm I would guess 10,000-20,000.
I wonder if it would be less rounds than that with a steady diet of all premium Underwood loads.
Quote from: Intercooler on August 02 2012 10:20:08 AM MDT
Maybe a Shock Buffer would do the trick?
By the time anything moves at all, the forces that cause the slide to eventually crack are long over. The slide cracks in question are caused by the stress of keeping the breech locked, not by the momentum of the slide during cycling.
Quote from: REDLINE on August 02 2012 10:41:00 AM MDT
Quote from: sqlbullet on August 02 2012 09:55:40 AM MDT
For a 10mm I would guess 10,000-20,000.
I wonder if it would be less rounds than that with a steady diet of all premium Underwood loads.
That is based on full bore 10mm loads. If you back off to 180 grain at 1200 fps, you should get somewhere between 38 super and 45 acp life out of the slide, since you are running at the same MAP chamber pressures as those rounds.
Would you limit what you said to quality firearms?
I wonder how that might vary between different frame/part manufacturing tecniques like: cast, machined, forged, electro-chemical... Not to mention how the difference between cro-moly and stainless steel might affect the outcome. I don't know, just throwing some food for thought out there.
Yes. That assumes forged or bar-stock machined slides. STI comes to mind.
There are some changes that a really sharp engineer might make to the slide that would help some. Minimizing stress focus points.
Yep, a sharp engineer would get rid of all those sharp inside corners! And make the slide a little thicker. I'm surprised nobody makes beefier 1911 slide? It wouldn't have to add much weight, and wouldn't take a rocket scientist to figure out.
The short frame rails of the 1911 are another concern for high energy loads like the 10mm though. The CZ design (ala Witness) is great in that respect, although it has other issues.
Quote from: Yondering on August 02 2012 12:20:14 PM MDT
Yep, a sharp engineer would get rid of all those sharp inside corners! And make the slide a little thicker. I'm surprised nobody makes beefier 1911 slide? It wouldn't have to add much weight, and wouldn't take a rocket scientist to figure out.
It has been a few (19) years since I really looked closely at a Glock slide, but this is the area I think it is really built for the 10mm. The way the barrel locks into the slide coupled with a flat breech really go a long way to making it both stronger and more durable.
I believe a purpose built 1911 from the ground up toward handling all a 10mm can offer, at at least a semi-reasonable price point would probably generate alot more attention than most could imagine. If it existed I would own it.
Quote from: Intercooler on August 02 2012 10:20:08 AM MDT
Maybe a Shock Buffer would do the trick?
The hammer spring in my 2012 RZ-10 seemed light for a 10mm.The sticky on a 1911 forum shows them to be 18.5 pounds,the same as their 45acp's.I detailed stripped my RZ-10 and put a wolf 21 pound spring in it.I polished the sear nose and hammer hooks with ceramic white and ruby stones and the trigger breaks at 4 pounds with no creep.It feels like 3 pounds.I use a wilson 22 lb FL guide rod system with shock buff.It runs flawless and is very accurate.I'm impressed with the quality inside and out.They only made 50 for 2012 and very glad I got one.I shoot mostly 180 LFN's over 6 grains WSF.Light recoil and shoots under 2 inch at 25 yards.
'10d' Nice gun. Thinking about getting a RZ10 myself.
10d where did you get yours? I got lucky and tried to pass on the deal... I was out the door for $1150 shipped.
I really love mine and now I see they are $1400 on up.
Im gonna chime in and opted to keep my Witness Match with 180's from Underwood and 200's with a 18 lb spring.I reserve more powerful loads for the Glock.I know the Match can handle more,but is it really prudent,no.That damn Glock jut rocks.That was my intention and it works.Of course the lite stuff is used for punching paper.The Glock and Witness are like "Jacob and Esau".
Now Now. You can't tell me you like the G20 as much as the Match.
Quote from: pacapcop on August 07 2012 08:07:40 PM MDT
That damn Glock jut rocks.
The G20 and G29 are awesome having the simplicity (even with numerous safety measures built in), durabilitly, round count capacity, and unerring reliability, all at the same time in a 10mm package. I think Mr. Glock simply kept cosmetics to a minimum to show he wasn't greedy, giving other manufacturers a chance in the marketplace. Still something to be said about a blacked out look except for the white in the sights. Truely an engineering feat! Personally, I wouldn't want it any other way. Guess that's why I own them both.
Quote from: Intercooler on August 07 2012 04:36:23 PM MDT
10d where did you get yours? I got lucky and tried to pass on the deal... I was out the door for $1150 shipped.
I really love mine and now I see they are $1400 on up.
I got mine from a place in KC.It is single digit serial #.One of the first.I had to pay retail.I wanted to make sure I got one.You got a very good deal for a 2012.Hang on to it.Probably the only way to get a better 1911 in 10mm is to get a Nighthawk or Wilson Combat and you'll wait a long time and pay twice as much.STI and Fusion make very good 10mm's also.The 1911 trigger is second to none.When I get the time I'll probably get a EGW FPS and put small radius and taper on it.If done right it works well.If you mess it up your out the low cost of the part.Having a gunsmith do the work would probably work for sure.It is said to help reduce recoil and muzzle flip.Many 1911 users do the mod.Recoil doesn't bother me in 10mm.Shoot a 454 Casull and then a 10mm it seems tame.
Quote from: 10d on August 08 2012 11:46:02 AM MDT
Recoil doesn't bother me in 10mm.Shoot a 454 Casull and then a 10mm it seems tame.
That's a good point. So many current non-10mm shooters want to use 9mm as a baseline for recoil. Makes no sense. The 9mm is the weakest round available that still meets FBI protocol in choosing a round for
defense. The 10mm might take a little more practice than something like 9mm to control, but the 10mm is by no means uncontrollable.
10d hold of on the EGW flat bottom. I purchased one from them and they sent an 80 series. As it turns out when I had the stocker out it virtually is flat bottom. I didn't opt for them to send the 70 series after this and instead got a fancy guide rod cap in place of the right one. I have a thread on here with pictures of both.
A heavier recoil or hammer spring may be money better spent. I don't see a Razorback under $1600 now :P
I just looked at the pic you mention in the gunsmith section.The FPS is flatter and works well but a FPS can have a smaller radius than that and a taper towards the top to get full effect of the mod.From what I've read and seen from pictures on 1911 forums is the radius is smaller and has a curvature like 1/4 of a 1/16 drill rod when looling at the bottom of the rod and the taper towards the top is around 2 degrees.The taper gives a better hit on the firing pin and takes out the play between the hammer and FPS.
Many 1911 tuners use the mod.You don't need heavy recoil springs or hammer springs if done right.Every pistol is slightly different in tolerances and carefull fitting is needed sometimes.
I have seen the pictures of the taper from bottom to top. Haven't done it.
For 45 ACP this mod makes recoil seem a little softer, and the heavier mainspring is not needed at the slide velocity levels the 45 ACP produces. The heavier mainspring in 10mm helps dump the delta in velocity and gets the slide moving at the same basic rate as on the 45 ACP.
I plan to try the reverse taper in my CCO build.
Pop it out and look first. I have flat bottoms in both my Witness guns and really saw not much difference in the EGW piece. The stock Witness piece it was pretty night and day. Thread on that on here somewhere.
This is night and day on the Witness... not so much at all on the DW.
(http://sphotos-b.xx.fbcdn.net/hphotos-ash3/s720x720/538390_361794450525260_1482421251_n.jpg)
Quote from: Intercooler on August 09 2012 04:13:20 PM MDT
and really saw not much difference in the EGW piece.
The difference seemed pretty obvious to me in the pic you posted. Maybe you should post it here too, so people can see what you're trying to say without searching pages and pages of your posts.
This picture sucked really and I don't have the EGW to photo again.
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120627_223802.jpg)
He has the firearm right there and you wouldn't even need to remove it to really see. Only 5 minute job to pull it to see it is nothing like the Match stock block. If I thought it was really any different I would have had EGW send me the correct 70 but just not different really.
In the picture, it sure looks like the one on the bottom has a lot bigger radius. Not as big as a traditional .45 firing pin stop, but still more than the EGW. A little bit goes a long way...
Okay. I'll play... gives me a reason to pull my favorite pieces out. See if you can tell me which picture is of which pistol and if their is any noticeable difference. I would have just opted for it but it's wider #1 and just no noticeable angle there. It's only a $20 part though and to me the guide rod piece just seemed like a better option here.
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232106.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232316.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232345.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232409.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232424.jpg)
Two more
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232948.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_233028.jpg)
Quote from: Intercooler on August 09 2012 09:35:42 PM MDT
Okay. I'll play... gives me a reason to pull my favorite pieces out. See if you can tell me which picture is of which pistol and if their is any noticeable difference. I would have just opted for it but it's wider #1 and just no noticeable angle there. It's only a $20 part though and to me the guide rod piece just seemed like a better option here.
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120809_232106.jpg)
Just from the pics, the FPS on the left looks like the better choice for the 10mm.
This post at M1911.org has a picture perfect radius:
http://forum.m1911.org/showpost.php?p=677430&postcount=79
Quote from: sqlbullet on August 10 2012 07:56:34 AM MDT
This post at M1911.org has a picture perfect radius:
http://forum.m1911.org/showpost.php?p=677430&postcount=79
No fair...members only. ;)
Sorry about that.
(http://fellingfamily.net/images/EGW_FPSBench.jpg)
(http://fellingfamily.net/images/EGW_FPS_Radius.jpg)
(http://fellingfamily.net/images/EGWFPS.jpg)
Says you have to be a member.
With the factory DW block it is like splitting hairs the difference.
I pulled my DW block for a picture. With it in place running the slide it does what it should and isn't like some extreme bad examples like the stock Witness.
(http://fellingfamily.net/images/EGW_FPS_Radius.jpg)
(http://i236.photobucket.com/albums/ff100/Intercooler2/20120810_123918.jpg)
Quote from: sqlbullet on August 10 2012 09:25:51 AM MDT
Sorry about that.
(http://fellingfamily.net/images/EGW_FPSBench.jpg)
(http://fellingfamily.net/images/EGW_FPS_Radius.jpg)
(http://fellingfamily.net/images/EGWFPS.jpg)
Excellent picture of the mod.A reverse taper fitted to take out play between hammer and FPS would make it perfect.A picture of a reversed tapered FPS and the way to show how it's fitted would probably help the guys see how the mod works so well for a 10mm.I'm not very computer smart or I'd do it.This mod is a very good thing for a high performance round like the 10mm.
Here is a pic of a tapered stop and an stock stop.
(http://fellingfamily.net/images/egwTaper.jpg)