racer-x Posted March 31, 2017 Author Share Posted March 31, 2017 On 10/8/2016 at 6:49 PM, cecil said: don't know this for fact... but.. someone told me that shooting 115's versus 124's is more damaging to a slide on a major gun... I've heard that as well with Limted guns. However, the specific instance I know of with lighter bullets and a slide crack was most probably caused by the reduced recoil spring used with the lighter bullets. Seems like slide velocity would be the primary variable for tearing up a good slide. I did some comparisons between 170 and 175PF 115 & 124gr bullets last week. Mostly trying to determine what shot the best between those loads, but I saved brass from each as well. The primers in the brass from the 124gr loads were flattened slightly more than their same PF 115 counterparts. Not an accurate pressure test, but all I have to go on. The 115 loads have more powder & gas and that should retard rearward slide velocity more than the 124 loads of same PF. Assuming the same recoil spring, there should be less impact & stress on the slide. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted April 1, 2017 Share Posted April 1, 2017 I admit to having OLD eyes, but I don't see the difference between the 115's and the 124's ... Link to comment Share on other sites More sharing options...
kneelingatlas Posted April 1, 2017 Share Posted April 1, 2017 On 10/4/2016 at 1:18 PM, juristrosins said: Just wondering if it relates only to 2011 platform? Somebody know anything to say about CZ? I've used and abused all manner of CZs, never cracked a slide Link to comment Share on other sites More sharing options...
kneelingatlas Posted April 1, 2017 Share Posted April 1, 2017 5 hours ago, racer-x said: The primers in the brass from the 124gr loads were flattened slightly more than their same PF 115 counterparts. Not an accurate pressure test, but all I have to go on. This agrees with my experience Link to comment Share on other sites More sharing options...
racer-x Posted April 1, 2017 Author Share Posted April 1, 2017 9 hours ago, Hi-Power Jack said: I admit to having OLD eyes, but I don't see the difference between the 115's and the 124's ... It's a pretty minimal difference to be sure. The edges of the primer bottoms are a little less round on the 124's. Easier to see in natural lighting with your eyes than in the pic. The main point for me was that it was not what I was expecting. With the higher powder charges, I was looking for the 115's to show signs of higher pressure, and the primers didn't show that. It seems like the 115's reduced mass to accelerate and reduced bearing surface offsets the higher powder charge, and then some. Link to comment Share on other sites More sharing options...
juristrosins Posted April 3, 2017 Share Posted April 3, 2017 On 01/04/2017 at 6:52 AM, kneelingatlas said: I've used and abused all manner of CZs, never cracked a slide Major loads too? Were they TS type slides or Shadow? Link to comment Share on other sites More sharing options...
kneelingatlas Posted April 3, 2017 Share Posted April 3, 2017 13 minutes ago, juristrosins said: Major loads too? Were they TS type slides or Shadow? Major loads, all kinds of slides: CM, TS, Shadow, SP01, 75B SA Link to comment Share on other sites More sharing options...
DVC1911 Posted April 3, 2017 Share Posted April 3, 2017 There are number of factors involved, primarily how well the gun is fitted. I have fired 60,000 rounds on my 9mm major open gun. All 170+ power factor loads. I am going to wear the barrel out before I break the slide. In 26 years of IPSC, I have only cracked one slide, that was a caspian, and they replaced it under warranty. That was 20 years ago. I currently use STI or SVI slides. I have not had any cracking issues on them. If the gun is built right it should not break. Link to comment Share on other sites More sharing options...
tyler2you Posted April 4, 2017 Share Posted April 4, 2017 If you do end up running a polymer buff, this little trick will make them last nearly forever. I picked this up from log man on the 1911 forum. Link to comment Share on other sites More sharing options...
ClangClang Posted April 4, 2017 Share Posted April 4, 2017 I'm not sure what I'm looking at. Is that a ShokBuff and an AlumaBuff sandwiched together? Link to comment Share on other sites More sharing options...
tyler2you Posted April 4, 2017 Share Posted April 4, 2017 12 minutes ago, ClangClang said: I'm not sure what I'm looking at. Is that a ShokBuff and an AlumaBuff sandwiched together? It's actually an M8 washer filed to the shape of the buff. It just prevents the buff from getting chewed up. Link to comment Share on other sites More sharing options...
TacticalJesus Posted May 9, 2017 Share Posted May 9, 2017 Ok, so still new at all this so I have to ask. Was reading up on open guns and have a couple questions about some comments on here. How does a slide stretch? I would think you would have to get it really hot for that to happen....When a slide cracks it's from the force of the recoil, correct? So how does running a lighter recoil spring help? Wouldn't that cause it to do more damage to the slide? And how does a hammer spring have anything to do with recoil or cracked slide? I didn't think it had anything to do with that, that is more for trigger weight.....Like I said I'm just trying to learn more about open guns, shoot limited right now but i'm sure I'll get the open bug one day. Link to comment Share on other sites More sharing options...
kneelingatlas Posted May 9, 2017 Share Posted May 9, 2017 7 minutes ago, smitty0420 said: When a slide cracks it's from the force of the recoil, correct? So how does running a lighter recoil spring help? Wouldn't that cause it to do more damage to the slide? And how does a hammer spring have anything to do with recoil or cracked slide? I didn't think it had anything to do with that, that is more for trigger weight... First off, I don't think lowering the hammer spring weight is a good tactic for lowering the trigger pull weight, that's best accomplished with sear and hammer hook angles/polishing. The hammer spring and firing pin stop geometry play an important role in managing the slide speed when it impacts the frame, probably as much as the recoil spring. Link to comment Share on other sites More sharing options...
TacticalJesus Posted May 9, 2017 Share Posted May 9, 2017 Ok, so still new at all this so I have to ask. Was reading up on open guns and have a couple questions about some comments on here. How does a slide stretch? I would think you would have to get it really hot for that to happen....When a slide cracks it's from the force of the recoil, correct? So how does running a lighter recoil spring help? Wouldn't that cause it to do more damage to the slide? And how does a hammer spring have anything to do with recoil or cracked slide? I didn't think it had anything to do with that, that is more for trigger weight.....Like I said I'm just trying to learn more about open guns, shoot limited right now but i'm sure I'll get the open bug one day. I kinda understand the trigger pull, there is more to it than just the hammer spring. What is the purpose of the light(7lbs) recoil spring? would a 10/11 be better? Never thought about the hammer spring having much to do with it? Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted May 9, 2017 Share Posted May 9, 2017 4 hours ago, smitty0420 said: What is the purpose of the light(7lbs) recoil spring? would a 10/11 be better? Mostly trying to optimize the recoil impulse and dot movement, even if it wears the gun more. It might cost hundreds of dollars to repair an Open gun after many years of service, but some people think it's worth the extra cost for the shooting benefit. If you're really serious about this game, the cost of a custom gun stretched over 3 years is the smallest cost you have - the cost of .38 super ammo (10,000+ rounds/year, the cost of match fees, and the cost of travel vastly overpowers the cost of the custom gun, or two. The reason you're befuddled is that you're trying to "save the gun" and the pros are NOT trying to save the gun - they're trying to optimize the recoil impulse, despite the extra cost of repairing the gun once in a while Link to comment Share on other sites More sharing options...
TacticalJesus Posted May 9, 2017 Share Posted May 9, 2017 not to worried about the cost right now. Just trying to make an educated decision when I decide to get an open gun. I know that at some point something is going to break, that seems to be the nature of the game. Just trying to understand the reasons behind it and learn form others. After reading a little more on it, makes since. Now I just have to go down the rabbit hole of 9 or 38!! gotta get my hands on some to try out to decide. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted May 9, 2017 Share Posted May 9, 2017 24 minutes ago, smitty0420 said: Now I have to go down the rabbit hole of 9 or 38!! The "difference" is tiny Nothing wrong with .38 super except the cost and inconvenience of BRASS. BUT, if you buy new brass, shoot it 3-4 x in practice, and then shoot it and leave it at matches, there is NO disadvantage. Costs 3 cents/shot. BUT, when you shoot 9mm Major, there is Very Little Difference - almost none. And, then you don't have any brass issues. You can get brass for Free, or for 3-4 cents/piece. Link to comment Share on other sites More sharing options...
Racinready300ex Posted May 9, 2017 Share Posted May 9, 2017 2 hours ago, Hi-Power Jack said: The "difference" is tiny Nothing wrong with .38 super except the cost and inconvenience of BRASS. BUT, if you buy new brass, shoot it 3-4 x in practice, and then shoot it and leave it at matches, there is NO disadvantage. Costs 3 cents/shot. BUT, when you shoot 9mm Major, there is Very Little Difference - almost none. And, then you don't have any brass issues. You can get brass for Free, or for 3-4 cents/piece. For me there are brass problems with both, with 9mm you have to pick out the cases with the little step inside of them. I found this to be a hassle, and I had two split and leave the front half of the case in the chamber. Pain in the ass to get out, that's when I started sorting 9 brass. I would buy my brass online pretty cheap use it a couple times and leave it at club matches. I also have a super, you have to separate out super vs super comp but my gun would run SC at about 99% so if one got mixed in it probably wouldn't matter. But I always found any sneaky SC's when I case gauge my ammo anyway. I marked all my brass and was able to pick up 90% of it at most local club matches. Of course this means I had to look for my brass, which marking made a lot easier. I'd buy the brass online once fired at like ten cents and use it 10 times or more easily. As long as the gun runs 100% it wont matter much what you're shooting. What will matter is how much you a shooting it. Link to comment Share on other sites More sharing options...
ShortBus Posted May 9, 2017 Share Posted May 9, 2017 The swaging backup die hits the cases ledge that have the stepped case and stope the press, i back up just a touch and throw the offending piece of brass away and continue on loaded. When loading for majors I also look info every case as it rotates out of the feeder arm just as a back up in case the backup die misses one (which I don't think it ever has). I had one seperate at a match, I feel your pain. Link to comment Share on other sites More sharing options...
kimberacp Posted May 9, 2017 Share Posted May 9, 2017 (edited) the way it was explain to me about the cracking, was that there are two opposing energy forces, the slide is moving backwards and the bullet exiting forward and that the barrel lugs not completely disengaged from the upper lugs. that is way most of the cracks are around the ejection port. could it also be the same idea as to the recoil impulse in major 9mm, compared to that of a .223 with a 16" barrel, carbine gas length tube? are not .223 case rims being shredded off at the extractor or failing to extract from the chamber because of the pressure?? JMO Edited May 9, 2017 by kimberacp adding text Link to comment Share on other sites More sharing options...
HotrodMachinegun Posted May 15, 2017 Share Posted May 15, 2017 It's my completely uneducated opinion that most of the cracked slides are from too much lightening in too many key places. I have a single stack .38 super thats around 30 years old and it's still going strong but theres not a single lightening cut in it. My 9mm major I bought off my shooting instructor for a song because it had a cracked slide but he had put an astronomical amount of rounds through it. When I replaced the slide I just did some basic lightening at the back of the slide and cut the slot for the popple holes. We'll see how long it lasts. Link to comment Share on other sites More sharing options...
Steve RA Posted May 15, 2017 Share Posted May 15, 2017 I'd think the slide lightening would be a major contributing factor. As you remove portions of the slide it can certainly tend to weaken it. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted May 15, 2017 Share Posted May 15, 2017 (edited) Hello: From what I am seeing it maybe the type of steel that is being used now is not that great. The grain structure seems very course. The heat treatment may not be very even on them as well. Thanks, Eric Edited May 16, 2017 by Aircooled6racer Link to comment Share on other sites More sharing options...
troupe Posted May 16, 2017 Share Posted May 16, 2017 I agree Eric. I remember back when folks shot the 9x25. The slides did not crack like the slides today, and there was not a harder round, major power factor put through a 1911 designed gun. The round was brutal on guns. Shear the top lugs from the slides and barrels with so much down force from the comps. Even Springfield slides did better than the majority of the slides out there. Caspian has the best track record going. Lets see what the new PT slides will do. It is just to easy to blame the 9, when I think the problem is in the metal. That is only 35 years of experience and thousands spent for some great memories. Link to comment Share on other sites More sharing options...
Jerry Anderson Posted August 15, 2017 Share Posted August 15, 2017 Pressure. I've seen it a lot. Link to comment Share on other sites More sharing options...
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