Help with 9mm 124gr lead cn bullets

[Ivan]

I picked up some lead 124 gr cn bullets. I am using SR 7625 at 4.0-4.2 gr powder charge. My pistol cycles perfectly but not consistent at all. Scattered all over the place. I started at 1.080 which had the worst group I've ever seen and finally ended up at 1.163. Decent grouping but still want better. I cannot lengthen the coal any further than 1.165 without falling into the groove of the lead bullet. Does anyone have any suggestions in how to get a tighter group? I normally load round nose bullets of lead or fmj or plated. I've never loaded a cn bullet and may not again if I can not get a good grouping. I generally load 10 and test, then re test, so far I've loaded and shot 150 of these rounds and at best 8" group at 25yds. With My LRN I am getting about 2" group at 25-30 yds. So if anyone has some insight I'd greatly appreciate y'all's help. Thank you.

 

[sgt z]

Try changing powders, adjusting charge, IDK.

 

[highstandard40]

I have never loaded for the 9mm, but i have read posts on another forum dedicated to cast bullets and a problem that many refer to with the 9mm is bullet diameter. If your current lot of 9mm bullets were purchased, there is little you can do to correct the poblem if it is indeed related to bullet diameter. If they were sized smaller than your gun requires, you are stuck with it. The 9mm is often plauged with this particular issue.......or so I hear.

 

[Redd508]

Are the bullets pre-lubed? Did you slug your barrel? I also suspect the bullets are under-sized for your barrel. If they are too small then powder coating may help. It will also prevent leading.

Lead bullets should ideally be .001-.002 over bore diameter.

 

[Ivan]

Redd508, thanks for the tip on bullet dia., I used my mic and measured them out. They are actually over sized. The mic out at .357". I then rechecked my other lead bullets that work great and they mic at .356 and my fmj at .355. I've checked my barrel and it is not fouled at all. These belts are precoated (lubed) with almost looks like powder coat paint. I'm going to try and figure out how to load a picture of them on here. Could the over size cause this issue?

 

[gandog56]

.357" ? Sounds more like they were sized for .38 spec/.357 mag. I actually have that done on purpose by Precision Bullets, oversize them for .38. They don't charge me any more if I request them so, I just have to wait till they run the next batch.

 

[capsix]

Although I have never used that powder, I would find a COAL that works well....no issues with magazine or feeding,etc. Stay with that COAL and load different powder charges...starting lowest and working up in .2 increments. You should be able to narrow down the powder charge to one that is most accurate and then adjust COAL if you are still not happy with the results.

 

[Ivan]

Sorry, I've tried and cannot figure out how to add a picture to a post

 

[Ivan]

Thanks guys, I've decided to not use these, since I did some homework and found that .357 is sized for 38/357. I don't want to damage my barrel. By playing with the powder I did get to about a 4.5" grouping. Not entirely happy with it, but ok for plinking and such. However I don't care that they are over sized. Thanks again for all y'all's input. Really appreciate it.

 

[scooterj]

Overcrimping the case will cause your issue. 0.357" bullets should work fine in 9mm.

 

[Ivan]

Overcrimping the case will cause your issue. 0.357" bullets should work fine in 9mm.

I am crimping just enough to close the bell, very little resistance is felt in my single stage press. If I am over crimping I cannot tell, no swaged lead or bulging is present. You are saying .357 bullets are fine for a 9mm? How is this so? I thought they were for 38/357. Will any barrel damage occur?

 

[Ivan]

Here is the bullets I picked up

 

[dixiejarhead]

Here is the bullets I picked up

Revolver bullets. With cast loads I only use Unique powder. You can resize those to .356 or .355 with a lee sizing die and they will work, but they are designed for .38/357 loads as you have figured out by now. If you have a lead pot, throw them in it and recast to your LRN. Also make sure you cold water quench your cast loads to add hardness. Soft lead bullets will do just what these are doing as well if the alloy is too soft.

 

[scooterj]

Not much bearing surface on those. Try a faster powder, 7625 is really slow burning.
If you slug your barrel, it's probably going to be larger than 0.355". Not many mfgs hold their tolerances that tight.
Lead bullets should be 0.001 - 0.002" larger than the bore.

 

[Ivan]

Ok, good to know. How ever since I am still much a noob, what does slugging the barrel mean?

 

[scooterj]

Slugging is pushing a soft led pellet through the barrel so you can measure the diameter of the grooves

 

[Ivan]

I really appreciate all of your comments and help, thank you all

 

[Redd508]

.357 wont hurt your barrel. I'm having more accuracy problems with too hard of an alloy and water quenching. The bullets will not engage the rifling properly and groups open up. 50/50 coww and soww unquenched did tighten up the groups but i may load straight soww. My velocities are below 1100 fps so leading isnt an issue. I'm still trying to find the right powder and charge to maximize accuracy. In my case a heavier bullet might be the answer, not a harder one.

 

[gandog56]

Slugging is pushing a soft led pellet through the barrel so you can measure the diameter of the grooves

I've pulled a few slugs from a barrel. (HIC!)

 

[dwr461]

I had a similar problem. The solution for me was that my dies were fouled. I was not expanding the case mouth enough. Sometimes the case would cut the Lube grove/bullet base enough that the bullet would tumble. It would not happen with every round. So double check your press.


Dave



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