.357 Magnum for the Coonan semi-auto

[Chaz88]

I really appreciate your time and input. I have a number of loads I would like to work on. When I started looking around for powder 2400 was not at the top of my list but none of my list toppers were available. I also have some H-6 I am going to look harder at loading with.

Back in the day, so to speak, I used unique to push hotter target / hunting loads with cast bullets but I do not see a lot of data for that in my newer loading books. Do you happen to know what powder is the equivalent of it today?

EDIT: Had brain fart unique would be the equivalent today.

[Sevens]

Still, though, not a bad question! Unique is still around, it is supposed to be a "newer, cleaner" formula... so as always, use proper techniques and re-work your old loads. Personally, I still find Unique to be a major annoyance to work with (it meters poorly compared to most other powders) and a more modern (somewhat) equivalent is Hodgdon Universal.

No surprise they named it "Universal", which is fairly close to sounding like "Unique." Load data is NOT interchangeable, but it does seems as though Universal can be used pretty much anywhere that Unique has been used in the past. I use a lot of Universal at my bench, but I don't care for it a whole lot in .357 Magnum. I have one chronographed load, and that's 6.3gr of Universal under a 158gr Zero JSP that returned a 972 FPS average -- a load that would not reliably run my Coonan. However, this was simply a leftover load that worked just fine in my revolvers, I never worked it further to develop it for use in the Coonan. All I know is that the few I had leftover didn't run the Coonan and I haven't worked with it since that time.

With cast lead bullets, I would imagine you could build a load using either Unique or Universal that likely would run the Coonan.

If/when you do... report back in this thread!

[Chaz88]

Load update for my Coonan.

Loaded some 125grn plated bullets over 14.0grn of 2400.

Did not cycle the gun reliably. Might try again after it is broke in better.

158grn over 14.0grn 2400 work great.

[Sevens]

Hmmm. A plated 125 in .357 Magnum is going to want to run quite a good bit over "recommended" velocity for a plated bullet. I ran some 125's through mine pushed by Alliant 2400, but those were well over 1,400 FPS, and I used jacketed bullets.

I do have a great load running 125's out of .38 Special brass at +P velocities, using the supplied accessory 10-lb spring. This load runs like a champion and never gives me a stitch of trouble, but it's not really like shooting .357 Magnum from a Coonan. It just isn't the same experience.

I run a lot of these 125gr .38's because my club doesn't want magnum pounding on their steel plates. So I run the heck out of 'em with hot .38's.

[noylj]

You can get a lighter recoil spring to shoot lighter loads.
You can also get jacketed bullets from PowderValley: Zero 125gn .357 JHP--or Montana Gold or Precision Delta and not have to worry about plated bullets.

[WillyBow8]

I am having some difficulty finding a good handload for the Coonan 357. I've tried 158gr plated RN with anywhere from 7.5gr to 8.2 gr of Unique. I've been unable to find a load that will eject well (stove-piping a big problem) and reliably lock open on the last round. Does anyone have any experience with this handgun and loads for it?

[Chaz88]

http://thefiringline.com/forums/show...=466534&page=2

There are number of loads in that thread.

I have just started loading for that gun and have had good results with 158grn plated bullets over 14.0grn 2400 in a .357 case.

I am not sure, I do not have data in front of me, but I think Unique might be a little too fast for the loads needed to run the Coonan.

I have also had some problems with locking open on the last round but I am not going to worry much tell it has a good 500 rounds through it for break in.

[NoSecondBest]

I had two of the original Coonan's back in the early 90's. Both shot very well and they were like any 1911 semi auto, they needed the right spring to work properly. If the new guns are built the same as the originals, get some replacement springs of different weights and use on that will allow the gun to cycle properly while not allowing it to slam too hard when cycling. The originals used the same springs that the 1911 45s used. I can't remember which springs I used with which loads back then but I know I had a pretty good selection of them and just used what worked best with what ever load I was using. Those guns back then shot lights out.....an inch or less at 25yds off bags with the right loads. Should have kept one of them.

[Dain Bramage]

My efforts mirror Chaz88. The Coonan does not like medium or weak .357 loads. I could not get any of my HP-38 loads to work. It also does not like rounds with a stepped ogive, like SWC. Don't use the provided .38 spl spring with weak .357 loads either. It will not work.

However, it does like full power 2400 charges (13gr+) with 158gr LRN or TC hardcast bullets. It has also never malfunctioned for me with commercial JHP.

It is what it is: an accurate, hard hitting, semi-automatic pistol that has an energy floor below which it will not operate consistently.

[Brian Pfleuger]

Threads merged

[WillyBow8]

Thanks to all, great info! I've concluded that Unique is the wrong powder for this application. I will likely try H110 or 2400. Thanks again for the good feedback.

[Chaz88]

Hope you have better luck finding H110 than I have. That is what I wanted to start with.

[WillyBow8]

Thanks Chaz, have you had the same problem with 2400?

[Chaz88]

Thanks Chaz, have you had the same problem with 2400?

I have had no problems ejecting and feeding the next round. I have had some problems with locking open after the last round. At this point I am attributing it to break in and possibly one mag needs to be tweaked a bit. The problem is inconsistent and is a little more prevalent with one mag over the other.

I have not run enough rounds through it yet to pin down a cause. I think it is mostly break in. After a couple hundred more rounds I will start to worry if things are not smoothing out.

I really like shooting this gun but did not expect flawless out of the box because it is a relatively unique pistol.

[HMC8404]

I doubt anyone can match this nightmare:
After finally getting the money to order my new Coonan Classic about one year ago, I made my order. The wait was about six months at the time. My FFL was a large farm, feed, hardware, guns..."you name it, you'll find it" store in Great Falls, Montana. I did the snowbird thing in AZ for the winter, and had just arrived, when I was notified that my Coonan had arrived. Overjoyed, I asked if they could keep the gun for me when I returned in 3 months. The gun dept told me "no problem", that it would be in their safe until I returned. Upon my return, I picked up the gun. It was just as gorgeous as I thought it would be. I brought it to an indoor range for the initial test run. The first five rounds went down range smooth as silk, and accurate as I was. Perfect...almost. when I fired the sixth round, I managed to hit the acoustical ceiling, and got some strange looks from the booth beside me as the particles fell. What had happened is the last two rounds went fully auto, and I didn't even realize it until trying it again...same thing. I called Coonan, and they said it may have been some type of bump I was doing with my finger. I tried again with more control as ever. Same thing. I ended up sending the gun back to Coonan to have them look at it. Two men from the Coonan team talked to me, and said that "someone" had done an extremely poor trigger job on the gun, making it very dangerous, and had even done some filing under the front sight for some reason unknown, making it loose. I felt like crap trying to explain that I would never attempt such a thing, and that I have never even opened up a gun before. They must have trusted me, because they did replace all parts to bring the gun back to specs for free. That Coonan was at one store for three months "secured" until I received it. Someone in that gun department got into my Coonan and butchered it. Why? That's the big question. There were several guys working in the department, so I couldn't pin it on any one person. Talk about ******! True story. BTW, Coonan Classics are one of the finest guns out there IMO. If you want one, don't hesitate...they are a work of art!

[Petespacking]

This has been an interesting thread. I waited thirteen months for my Coonan and finally got it this spring and it has been fun breaking it in and seeing how the gun really does get better with rounds down the tube. My current load works well with both plated and jacked 158 grain bullets over 15.5 grains of Winchester 296 and CCI magnum primers. Totally reliable cycling and last round lock open. They're great guns and always draw a crowd when I shoot. I love the ring of fire, which is quite pronounced, with this particular load.

[Deja vu]

Been playing with Power Pro 300MP. Its pretty cool stuff. The loads in the Aliant manual are pretty hot. I have since ran out of gold dots so have been using the Hornady reloading manual with Hornady bullets. The Hornady manual is alot slower than the Aliant manual. Lower charges as well.

I mostly load with 300 MP and H110 and 2400 in the heavier bullets. With bullets in the 158+ grain catagory you can down load them and my gun with cycle subsonic 180 grain bullets reliably.

The 6 inch barrel likkly helps increase back pressure some.

p.s. I think my spell check is broken.

[Deja vu]

Been loading the Hornady HP 140 grain bullets with the 300MP powder.

I have read to use standard primers (not magnum) After a little testing I have come up with a decent load that shoots pretty consistently. I am not sure how much higher I could go but this is fine. I dont need to go any higher.

140 Grain Hornady, Coonan 357 magnum 6 inch barrel. Starline Brass, Federal standard small pistol primers, Lee Factory Crimp Dye with 1/2 a turn for crimp level. (medium crimp). Charge is 19.5 Grain 300 MP powder. As always I don't recommend this to any body this is just from my gun.

I was unable to find such a load so I worked up one used the 300MP recipes in the Alliant powder for the 125 and 158 grain bullets. I found the max charge listed for 125 grain was 22.3 and for the 158 grain is 18.6 from the Alliant reloading manual. So I doubt I am at max but I am happy with what I am at.

1523
1525
1532
1550
1529
1539
1525
1518
1547
1531

I don't know how to figure out SD but it seems pretty good. The Range from the muzzle to the chronograph is about 15 feet.

p.s. one thing is weird with this powder (maybe its just me) but the tone of the gun sounds lower than with H110 or 2400.

[Sevens]

Standard deviation is a rather complex mathematical formula. It's an interesting detail to have on a load, I do believe that.

It's far too complex for me to understand and there is probably a calculator that google can find to handle it, and I'm sure google could spit out a formula for it that would make my brain EXPLODE just looking at it.

But I can safely suggest that if the numbers you posted were all the rounds you shot, and you didn't throw ANY out, then your SD on that load is going to be really niiiiiiice!

[Chaz88]

I think your mean is 1531.9 and your SD is 9.9

[Deja vu]

I have been using laser cast 180 grain bullets.

Random Brass
CCI Small pistol magnum primers
Unique powder.

My gun cycles about 99% of the time with 5.3 grains so I upped it to 5.5 grains and so far so good. Chronograph says about 1030 FPS so its subsonic and still cycling. I have ran it as hot at 6.0 grains. Even subsonic its pretty loud.

[Sevens]

I am extremely surprised that load runs! But likely an absolute pleasure to shoot.

[Deja vu]

My Coonan Classic is a pretty early model. Got it in 2011 and its serial number is in the 200s it also has been shot a lot so the spring is very broke in. But even at 6 grains its still pretty easy on the shooter. The Coonan runs pretty well even at slow speeds if the bullet is heavy enough.

The idea came from taking my Enhanced CCW class with my Coonan and the shop at the time only having Remington 180 grain HPs that I later discovered where running about 1100 and ran like butter.

I decided to try my own. Usually unique is not a good Coonan powder but it seems to work with the 180 hard cast bullets.

[JPT]

I've had mine for a little over a year. My current go to load is 125gr Hornady XTP with 17.1gr of IMR 4227. pretty accurate for me and cycles the slide without throwing the brass a mile.