blacklab Posted April 7, 2018 Share Posted April 7, 2018 It's been a few years since I broke in a new gun but I just had a new open 2011 built by a local gunsmith and was wondering what spring would be the best for break in. It's a 5" slide that weighs about 10.2ozs with a kkm bull barrel and a 3 port comp made by Aftercooler6racer. It was built for 3 gun so it will only be shooting minor loads. My loads are 9mm 115gr with 5.1gr of Autocomp. I was thinking of using a 6lb spring to start. My old open gun has a 8lb spring, but the new will not cycle on 8lbs. I don't want to go too light and risk cracking the slide but I would like to try and keep it reliable through break in. Any thoughts would be appreciated. Link to comment Share on other sites More sharing options...
drewbeck Posted April 7, 2018 Share Posted April 7, 2018 What did your GS say to do? Link to comment Share on other sites More sharing options...
tcazes Posted April 7, 2018 Share Posted April 7, 2018 The last 2 new guns I had were reliable out the box by atlas. Just trust your gun smith and go put 500 rounds through it Link to comment Share on other sites More sharing options...
blacklab Posted April 7, 2018 Author Share Posted April 7, 2018 6 hours ago, drewbeck said: What did your GS say to do? He had a 8lb spring in it, but it doesn't cycle with the 8lb. Link to comment Share on other sites More sharing options...
Sprig Posted April 7, 2018 Share Posted April 7, 2018 Did he know this was going to be used for minor ? I have to run a 7# and 6.0 gr of AC to get mine to cycle with minor . You should ask the builder what load and spring he recommends for minor . Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted April 7, 2018 Share Posted April 7, 2018 1 hour ago, Sprig said: You should ask the builder what load and spring he recommends for minor . +1. If 8 is too heavy, I'd try 6, if the builder were unavailable Link to comment Share on other sites More sharing options...
Sarge Posted April 7, 2018 Share Posted April 7, 2018 I run an 8 in 9MAJOR open gun. It won't come close to cycling a minor load and it's well broken in. Link to comment Share on other sites More sharing options...
drewbeck Posted April 7, 2018 Share Posted April 7, 2018 He had a 8lb spring in it, but it doesn't cycle with the 8lb.I’d still ask him about the situation even if it’s what he put in it. Are you sure it’s only the spring weight that’s causing the issue? It could be a number of things that’s why I’d talk to him Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted April 7, 2018 Share Posted April 7, 2018 I run a 10# spring in my 9mm Major TruBor, and if the gun is really clean and really well lubed, it will do a pretty decent job with factory Remington green box at PF127 Link to comment Share on other sites More sharing options...
blacklab Posted April 8, 2018 Author Share Posted April 8, 2018 10 hours ago, Sarge said: I run an 8 in 9MAJOR open gun. It won't come close to cycling a minor load and it's well broken in. Do you have poppel holes? 8lb works great on my old gun with minor loads and no holes. Link to comment Share on other sites More sharing options...
blacklab Posted April 8, 2018 Author Share Posted April 8, 2018 10 hours ago, drewbeck said: I’d still ask him about the situation even if it’s what he put in it. Are you sure it’s only the spring weight that’s causing the issue? It could be a number of things that’s why I’d talk to him Sent from my iPhone using Tapatalk I'm 98% sure its the spring, I did a slow mo video and the slide comes half way back and the empty shell goes back in to chamber. Link to comment Share on other sites More sharing options...
Sarge Posted April 8, 2018 Share Posted April 8, 2018 11 minutes ago, blacklab said: Do you have poppel holes? 8lb works great on my old gun with minor loads and no holes. Nope Link to comment Share on other sites More sharing options...
blacklab Posted April 8, 2018 Author Share Posted April 8, 2018 2 minutes ago, Sarge said: Nope Oh, I wonder why they work so different. 115gr over 5.1 autocomp works great in my old one with 8lb. I gave the gunsmith my old one and told him to clone it. He did a nice job, it just doesn't like 8lbs. Link to comment Share on other sites More sharing options...
drewbeck Posted April 8, 2018 Share Posted April 8, 2018 11 minutes ago, blacklab said: I'm 98% sure its the spring, I did a slow mo video and the slide comes half way back and the empty shell goes back in to chamber. But what is the cause of the resistance? A spring may overcome the issue but doesn’t mean it’s the right answer nor the real problem. The root cause could be the link, lower lugs, barrel bump, upper lug timing, barrel clocking, hood length, etc. Unless you know what to look for you’re guessing. Most open guns will run 12-14lb springs on box ammo, it’ll be sluggish but functional. just an opinion Link to comment Share on other sites More sharing options...
drewbeck Posted April 8, 2018 Share Posted April 8, 2018 What shape is your firing pin stop and what is your mainspring weight Link to comment Share on other sites More sharing options...
blacklab Posted April 8, 2018 Author Share Posted April 8, 2018 3 minutes ago, drewbeck said: But what is the cause of the resistance? A spring may overcome the issue but doesn’t mean it’s the right answer nor the real problem. The root cause could be the link, lower lugs, barrel bump, upper lug timing, barrel clocking, hood length, etc. Unless you know what to look for you’re guessing. Most open guns will run 12-14lb springs on box ammo, it’ll be sluggish but functional. just an opinion 12 to 14lb springs? I didn't know open guns worked with springs that high. My steelmaster has a 8 and my CK has an 8. Anything higher and it stovepipes. I never seen any damage to the frame or slide. I think the main spring is a 15lb but I cant remember off the top of my head. Firing pin stop has the correct curve. I told the gunsmith to clone my CK gun. I figured it would have to loosen up a little and then put a 8lb back in it. He put other open guns together for people and no one ever complained so everything else should be right. I hope. Link to comment Share on other sites More sharing options...
drewbeck Posted April 8, 2018 Share Posted April 8, 2018 My point is that the entire gun is a system, there is no “correct” FPS, and there are no correct spring weights. The only thing that matters is whether the system is running and yours is not. Call your GS. what you don’t understand is that your FPS, mainspring, and recoil spring are are working in conjunction with each other to control the slide speed and return the gun into battery. I can make make the same gun run with a 25lb mainspring and FPS shaped for it with a 5lb recoil spring, and the same gun will run with a 15lb mainspring and 14lb recoil spring with a big radius FPS. eveything is related, ask you gs what he thinks based on his “normal” Link to comment Share on other sites More sharing options...
digi531 Posted April 11, 2018 Share Posted April 11, 2018 Try to keep it simple at first, install a 7 # spring and try it out, it wont hurt the gun. If not working then up the load slightly and try again. If still not functional, then back to the smith for examination. Link to comment Share on other sites More sharing options...
blacklab Posted April 15, 2018 Author Share Posted April 15, 2018 Looks like it has to so back. The only way I can get it to run is with a 5lb spring. Link to comment Share on other sites More sharing options...
drewbeck Posted April 15, 2018 Share Posted April 15, 2018 If it runs with a 5lb spring, it tells you the gun runs. What kind of oil or grease are you putting in it? What does the slide feel like without a recoil spring in it? If it’s smooth and not sticky something else is binding, could be ammo, could be your grip, could be the coating, mags, or a bunch of other things Link to comment Share on other sites More sharing options...
Knguyen1904 Posted April 16, 2018 Share Posted April 16, 2018 I’m running a 5” slide in my 2011 and when I shoot minor factory loads I go from a 10 down to a 7 spring Link to comment Share on other sites More sharing options...
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