Maximum dose of N320 115 grain 9mm

[winter5470]

I have loaded over 12,000 rounds of 115 MG CMJ with 4.4 grains N320 OAL of 1.155. Out of my glock 19 I get an avg. 1121 ft/sec. PF - 129. That is what I have been shooting for 2 years. When I worked up the load if I used 4.5 grains I got an avg. 1133 ft/sec. PF - 130.

I just bought a springfield 1911 9mm. It runs on my 4.4 grain reolads but it will only lock the slide back half of the time. I have posted on another thread to get ideas. One suggestion was to increase the power factor to 135. My lyman manual shows max of 4.5 grains. VV website shows 4.5 grains max. Steves reloading page says 4.9 grains max. I am planning on going slow and make a couple dozen rounds as I increase the powder by .1 grain. But I have very little experience looking for signs of over-pressure loads. I will have a chrono to test the loads. So I am looking for general guidlines as to how much N320 people have "safely" loaded under a 115 grain CMJ loaded out to 1.155.

Thanks Again for your advice

Kurt

[Duke Nukem]

Vihtavuori manual shows 4.5 as max at 1.14 oal.

Pressures signs will vary gun to gun. Start at 4.5 and work up until you see signs.

Personally I would just put a lighter spring in the 1911.

[winter5470]

The lighter spring was the another option

[G-ManBart]

My VV guide shows 4.6gr with a 115gr Hornady XTP. Since a JHP takes up more case volume at the same overall length (which increases pressures) 4.6gr with an FMJ/CMJ would be safe...should be lower pressure. R,

[DWFAN]

How about a 124gr bullet? Would only need 1088 fps for 134pf. Might run the gun better, and have a little softer recoil. You'd also get to use less of that expensive powder per round. (I still think a 8lb spring would be beneficial also.)

Edited April 9, 2010 by DWFAN

[winter5470]

MG sent me a trail pack of 124 grain CMJ's last week when they shipped 4,000 of the 115 grain. So I can try a few but I have a lot of 115 grain I need to shoot before I can order more (or my wife lets me order more).

I think my game plan will be to make up some 4.5 grain and some 4.6 grain try those this weekend. If that does not work I will order an 8# spring. Unfortunaely at Midway (the only place I have seen them so far)the 8# springs are on backorder. Anybody have an 8# spring they want to sell?

Kurt

[G-ManBart]

MG sent me a trail pack of 124 grain CMJ's last week when they shipped 4,000 of the 115 grain. So I can try a few but I have a lot of 115 grain I need to shoot before I can order more (or my wife lets me order more).

I think my game plan will be to make up some 4.5 grain and some 4.6 grain try those this weekend. If that does not work I will order an 8# spring. Unfortunaely at Midway (the only place I have seen them so far)the 8# springs are on backorder. Anybody have an 8# spring they want to sell?

Kurt

Shooter's Connection has ISMI 8lb mainsprings in stock (just checked). Based upon some other threads I'm switching all my guns to Sprinco recoil springs (but not the recoil reducers). It seems they do more testing to ensure the springs are really the weight they're listed on the package. Most companies (ISMI, Wolf etc) just rate springs based upon the wire gauge and heat treating, but don't actually check the springs you buy.

http://www.sprinco.com/springs.html

[DWFAN]

Brownells will have the spring you need, you can link to their site from here in the vendor forum.

[winter5470]

G-man - the sprinco 8# is progressive. Is that OK?

[G-ManBart]

G-man - the sprinco 8# is progressive. Is that OK?

That should be fine. I ran ISMI standard 9lb springs in my Open guns until switching to the the Sprinco 9lb springs and they feel the same to me (and have run perfectly). R,

[gm iprod]

I have had reasonable experience with both Kimber and Springfield in 9mm. With a 130pf 9mm load I ran 11lb springs if the gun has had no other modification. 10lb if you put a shockbuff in. I tend to lean towards 1.125" with a Zero JHP and 4.4gr N320 for 1125fps. The shorter load length worked better in the Springfield with the newer style magazines that have the crimp in the front.

[winter5470]

I was at the range yesterday. Here is my chrono data: Temp was 80 degrees at sea level

115 gr CMJ MG 4.4 gr N320 Federal Match 1.157 avg. 1106 ft/sec. PF - 127

115 gr CMJ MG 4.5 gr N320 Federal Match 1.156 avg. 1125 ft/sec. PF - 129

115 gr CMJ MG 4.6 gr N320 Federal Match 1.156 avg. 1160 ft/sec. PF - 133

With all different powder and mag combinations - I had >90% slide lock (compared to 50% earlier in the week during the intial break in). No failures to feed etc. Maybe the gun just needs more break in. I will run 1500 rounds of 4.4 grains N320 thru it this week at a class before doing any mods, changing springs etc. The slide and trigger are definately smoothing out the more I shoot it.

Thanks to all who commented

Kurt