125 gr .357 Magnum

Cartridge: 357 Magnum

Brass: New Starline

Primer: WSPM

Powder: H110 19gr

Cartridge Cartridge Length: 1.599″.

Bullet: 125gr Hornady XTP #35710

Firearm: Coonan .357 with 5″ barrel

Shooting record: 9 shots (S48) 1428.5fps average, Extreme Spread: 191=1511-1320; StdDev 78fps; 1495, 1373, 1482, 1352, 1490, 1511, 1347, 1488, 1320

Approx drag: -4 fps / yard at 1488 fps, only first 25 yards measured.


Hornady 10th edition predicted 1400fps @ 18.9 grains.

Notes: Cycled Coonan, fun boom, but not totally overwhelming recoil.


Berry’s 45 Cal / 250 Grain Flat Point

Berry’s Bullets .45 LC 250 Gr FP. Fine totally-jacketed plinking bullet for 45 Colt, lots of fun at Sunnyvale Rod & Gun with a backlight

“Can withstand velocities up to 1250 fps.”. I measured the OAL of the bullet as: 0.6140 to 0.6125. It feels very slick. It was very visible when shot at night, almost like GlowAmmo. No crimp groove.

45 ACP

πŸ‘Ž Not a good fit for 45 ACP. To chamber reliably it had to be seated very deep. Deeper than I had load data for, and that made me very nervous about pressure. Western Powders Load Data says, 1.2″ OAL, True Blue Powder: 5.7gr @ 731 fps, 6.7 @ @ 839 fps and 20,889 PSI.

I did 1.2″ OAL, R-P brass, Rem 2.1/2 Primer, 5.7(??? Confirm!) TrueBlue. Would only plunk in a HOT barrel, sometimes. From a 5″ LesBaer I got Avg 665fps, ES 41 = 685 – 644, Std Dev 17.25 (8x), Labradar Series S133.

45 Colt

I used Hodgdon data as a baseline: New Starline brass with uniformed flash-hole, Rem 2.1/2 primer, #50 (3BR pistol) β‰ˆ 8.9gr CFE Pistol, Berry’s Bullets 250gr FP 1.5425″ OAL (Should be same capacity as 250 grain XTP, which is 0.6630 to 0.6650 long) high neck tension but light taper crimp, Lyman M expander.

984 fps avg, ES 73 = 941 – 1014, StdDev 19.95 (10x), Labradar Series: S150.

Approximate drag: -1.1 fps/yard at 980 FPS

Subjectively, I didn’t feel like they were very accurate, but they rang steel at 100 yards on demand.

I would buy them again at a good price. They are very clean. The lack of a crimp-groove hasn’t been a big deal so far, but it’s not ideal. I belive hey could be seated very deep, so strong crimp could be formed over the ogive. But then you’re on your own with load-data.

CFE Pistol + 45 ACP

Handloader magazine and Hodgdon have published some impressively fast loads using CFE Pistol. To my surprise, they deliver.

Hodgdon data: Winchester case, Fed 150 LP primer, 5″ 1:16 twist barrel, .451″ cast lead SWC, 1.225″ OAL.

START: 7.4 grains CFE Pistol 1,042fps 15,000 PSI

MAX: 8.2 grains CFE Pistol 1,142fps 19,600 PSI

Yes, the start load really is nearly 1050 feet per second, and it was faster than every other maximum load with that bullet!

I did: “Bullseye #2” 200 grain coated SWC from MBC, .452″, Brinell 12 (for bullseye), Rem 2.12 primer, #41.5 (3BR pistol measure) = 7.4-7.5gr CFE Pistol, 1.255″ OAL, mixed brass.

Labradar: S156; Reeds Indoor Range @ 25 yards

1012 fps (1007, 987, 1012, 1029, 1018, 1012, 1011, 997, 1035)), ES: 48 = 1035 = 987, StdDev 14.65 (9x)

Notes: Recoil was every bit as bad as loading up another powder to +P pressures to get the same speed. Some soot on the outside of the cases makes me think I was getting this speed at low pressure.

350 Grain 500 Linebaugh

Conclusions: πŸ‘Ž I can get some fast velocity with this weight, but overall I’m not a fan of it. I also get lots of variation (big case, small bullet). This velocity & weight combination can be matched with a 454 Casull, which will be cheaper and have a better BC. I’d rather let a 500 Linebaugh be a 500 Linebaugh, instead of trying to make it a high-velocity round. Recoil is less than with ~400 grain loads, but still a lot. I have to concentrate hard with both of them.

πŸ‘ 350 grain slugs and reduced (Trail Boss) loads make sense to me. But since all the slugs in this weight class came with gas checks, I pushed them hard. This WFN would be my first choice for reduced loads, because heavier slugs will do better at long range, so if you’re committed to a light slug it’s better to double-down on short-range performance with the flatter nose.

I used Starline Brass, and CCI 350 Primers for all loads. Firearm was a converted Ruger Bisley with a 7.5″ mag-na-ported barrel.

Cast Performance / Grizzly Cartrage used to make a 350 grain gas-checked .511″ slug, that you can find some load data for. Unfortunately it is discontinued. Cast Performance load data is a bit cryptic and says “H110 or W296 powder 29grns start 32grns MAX 1250fps” for their 350 grain slug. John Taffin used 29-31 grains of H110 for a 400 grain slug, so I felt safe in that range. I got:

Grains H110 Velocity ES Std Dev LabRadar
29 1308 94=1351-1257 32.2 (6x) S88
30 1346 42=1360 – 1318 16.53(5x) S89
31 1347 234=1416-1182 95fps (5x) S90

I couldn’t feel a difference in recoil between these three loads. It seems like I’d feel the 234fps ES, but I don’t remember. I didn’t check for position sensitivity.

Accurate’s Load Data (2016) says that a 7.87″ barrel using the Cast Performance 350 grain “WFN” gives 1,337 fps at a start of 26.6gr Accurate #9, maxing out at 1,485fps at 34,120 PSI.

Montana Bullet Works 500 LINEBAUGH, LBT, 350GR, LFN-GC looks to have the same dimensions as the (sadly discontinued) Cast Performance 350 gr WFN, even though it’s called an LFN. My scale showed 365 grains actual weight. I resized the slug to ~.511. 26.6 grains of Accurate #9 gave me 1371fps (1370, 1350, 1400, 1431, 1303, 1373, 1369), ES 128=1431-1303, StdDev 39.85 (7x), LabRadar S151, approximate drag -2.8 fps / yard (-2.65fps/yard @ 1303fps, -3.2fps/yard @ 1431fps)

The Montana Bullet Works LBT, 350GR, WFN-GC is noticeably flatter and shorter in length, and weighed 355 actual. I left it factory-sized at .512″ The same 26.6 grains of Accurate #9 gave me 1333fps (1274, 1403, 1353, 1373, 1346, 1247), ES 156=1403-1247, StdDev 59.78 (6x), LabRadar S152. Approx drag -3 fps/yard at 1270 fps and -3.6 at 1400 fps

Both loads were LOUD and Acc #9 was position sensitive. I could feel the difference in recoil when tipping the gun up or down before firing.

“Ruger Only” 45 Colt + 250 grain XTP

Hodgdon says 250 grain Hornady XTP, Winchester case, WLP primer, 7.25″ test barrel with 1:16″ twist.

H110 25.7 1,398fps 27,000 CUP

H110 26.5 1,455fps 29,800 CUP

I used 250 grain Hornady XTP, new Starline cases, WLP primers, Freedom Arms Model 83 with 6″ barrel and 45 Colt cylinder. 25.7 grains of H110 gave me (LabRadar S122):

Velocity: 1324 fps average (1317, 1374, 1334, 1290, 1339, 1345, 1322, 1320, 1279, 1323)

ES: 95fps = 1374-1279

Std. Dev 26.78 (10x)

Approx drag: ~3 fps lost per yard

Notes: LOTS of flash. Stiff recoil, about the limit of what I can tolerate comfortably with gloves. The huge flash and stout recoil makes this one fun.

Superheavyweight .357

I was curious what it would feel like to replicate classic 45ACP ballistics in a .357 Magnum. Especially since I had a Coonan .357 β€” aka a 1911 stretched and chambered in .357 Magnum.

I used Penn Bullet’s “.38 Caliber 230 Grain THUNDERHEAD” Bowling Pin Design, which is essentially a big bevel-base tube of lead with crimp-groves. The part that sticks out of the case is less than bore-diameter to reduce bearing surface and pressure. My lot weighed 240 grains actual, despite the name. Fortunately, the maker lists load data online, including pressure-test results for 38 Special! I didn’t see pressure-tested data for .357 Magnum, but they did say “In .357 cases, 9.0 grains of Accurate Arms #9 will get the job done.” I started quite a bit lower – I didn’t want to exceed “standard” 45 ACP speeds, and frankly such a heavy-for-caliber bullet is scary.

Second-hand and decades-old info from Accurate says (lightly edited for length):

We suggest the following.

Caliber: .357 Magnum with 230grain Penn bullet.
Barrel length: 6”
Application: PIN Shooting
Projectile data: 230grain Cylindrical design Length: 0.909”

Bullet seated on 1st cannelure: 0.525” = COL ca 1.664”

Powder: Accurate –no 9. (1st Choice)

Bullet weight: 230 grains. COL:

Start load: 8.5 grains (925 – 975 Ft/p/sec)

Maximum load: 9.5 grains (1025 – 1075 Ft/p/sec).

Bullet seated on 2nd cannelure: 0.625” = COL ca 1.564”

Powder: Accurate –no 9. (1st Choice)

Bullet weight: 230 grains.

Start load: 7.4 grains (900 – 950 Ft/p/sec)

Maximum load: 8.2 grains (950 – 1000 Ft/p/sec).

It’ important to note that:

1. SAFETY is our prime concern therefore:

1.1. The loading data is conservative, especially regarding the minimum or start load to ensure a safe baseline to work from.

1.2. The safety margin built into the start load might be more than the customary 10%.

To fit in the Coonan magazine, I had to use the second cannelure (shorter OAL).

In a 7.75″ test-barrel, with 38 Special case + Winchester WSP primer, 6.5 grains of Accurate #9 gave 815 fps at 17,567 PSI, and 7.0 gave 883 fps at 21,867 PSI.

In a 5″ Coonan I got:

Charge (grains) Velocity (fps) Spread StdDev Brass Primer LabRadar
Acc. #9 7.0 799 67 = 834.5 – 767.5 24.19 (8x) *-* WSPM S52
Acc. #9 7.0 808 98 = 852 – 754 29.45 (9x) A-P WSPM S53
Acc. #9 7.7 868 60 = 890 – 830 25.35 (5x) A-P WSPM S54

Notes: Smokey, but cycled the coonan just fine.

Polymer Coated (red) versions are now available from Badman Bullets

Coonan .357

πŸ‘ fantastic range toy or addition to a 1911 collection. Don’t kid yourself that it’ll be useful for hunting or defense. But if you’re thinking about one for any other reason β€” get it!

I purchased the .357 Coonan I’m writing about used, and do not know it’s full history. I know the factory made improvements since it was made, because the extra magazines I purchased from the factory at a later date were of a superior design. But improvements don’t change the core problem: long rimmed cartridges of varying power levels are kryptonite for an autoloading pistol. It doesn’t matter if it’s a super gun. The .357 Magnum is a revolver cartridge. Running .357 Magnum through an autoloader will cause problems. “Magnum” autoloading guns built around autoloading cartridges (10mm, 45 Super, 50AE, etc) do not have those problems. The handicap of a revolver cartridge is bigger than the magnum power it brings.

Why shouldn’t I buy it? Because it is not reliable.

It can’t be overstated that the physics of rimmed revolver-rounds works against any automatic pistol. In addition to feeding problems, my experience has been that malfunctions are significantly harder to clear because rims create extra interference-points. Normally, clearing a stove-pipe malfunction means just sweeping the brass away, and racking the slide. But the rim can catch on the next round in the magazine, or the magazine lip, or under the breech-face, or on a locking-lug, or on the roof of the chamber, etc… And when that happens, prying and fiddling is required. The rim-enhanced jams aren’t so serious as to require tools. But they take significantly more time to clear, and require a kind of stop-and-think problem solving that common malfunctions don’t.

I’m sure that it’s quite possible to find a load that runs 99.9% trouble free … but why bother, when you can shoot .357 Magnum in a revolver with none of these problems? Or “magnumize” a 1911 with a rimless 460 Rowland conversion. Or squeeze even more power from .357 ammunition with a single-shot T/C pistol that has twice the barrel length and no cylinder gap. Or buy a practical Glock in 10mm.

The answer for me is, because the Coonan is tremendous fun.

But for any application that needs .357 Magnum ballistics, there is a better option.

Can the gun function reliably enough to be fun at the range? Hell yeah!

if you take the time to find a load the gun likes, and stick to it, it will run. In my limited testing, a 180 powerfactor or above was where the gun would cycle regularly.

Let’s be clear: the occasional stoppage is well worth the huge fun of a huge fireball, but tolerable recoil.

That video is not me or my gear, but it accurately represents my experiences. As you can see, the gun does have a lot of kick. But it has enough weight and grip-surface to dampen and spread the recoil so that it isn’t painful. It will slow you down, but it won’t hurt you. It’s all bark and no bite. Wear extra ear protection though, because it is loud!

But isn’t the .357 Magnum so powerful that–? No. Sorry.

Don’t let that big fireball fool you! It’s unburned powder that didn’t help.

Yes, the .357 Magnum is more powerful than any common automatic pistol calibers. But it is not so ballistically superior that it’s worth major sacrifices. Be wary of high velocity numbers quoted on ammunition boxes β€”Β many of those numbers came from unrealistically long test barrels in labs. If you’re willing to make the kinds of exotic tradeoffs the Coonan makes, there are far more potent and practical platforms.

For bear defense with a 1911, Buffalo Bore sells a knockout 255 grain 984* FPS 45ACP+P . (Note: Buffalo Bore scrupulously underpromises 925 feet per second on the box, but Handloader #310, October 2017 chronographed 984 feet per second from a 5″ 1911.) That’s as much momentum as Elmer Keith’s hot 158 grain 1550 feet per second .357 loads.

Where .357 Magnum really shines over 45 ACP is of course speed. I’ve chronographed 1550 feet per second out of the Coonan. But so far I’ve only seen that speed with light bullets. Unfortunately light and fast bullets do not retain their velocity well over distance, and that tarnishes the biggest advantage that fast bullets give you: a flatter trajectory at distance. The reality is that a pistol is a short-range weapon, so it’s probably all theoretical anyway. I haven’t been able to hit anything with a .357 Magnum that I can’t hit with a 45ACP. More importantly if speed is your thing: 22 TCM would give you more of it in a handier gun: 2,000 feet per second from a 1911, without a distended grip frame. Or try an FN Five-SeveN with more capacity and less bulk than the Coonan.

Is it a 1911? Yes, it can be worked on like a 1911 with some proprietary bits.

I gave my gun an over-haul using a standard 1911 firing-pin-stop, sear, hammer, leaf-spring, grip safety, thumb safety, barrel bushing, and grip screws. The only non-standard parts I used were grips from Stoner CNC.

The manufacturer’s list of interchangeable parts was more conservative than my experience. I don’t know if this is under-promising and over-delivering on their part; the state of current manufacturing; or myself not recognizing the difference between “gunsmith fitting required” and “blacksmithing required”.

The mainspring housing is definitely proprietary. I was surprised to see that it has a narrower channel (1/4″ nominal) and a different mainspring-cap. Standard mainspring-cap-retaining pins work.

How are the ergonomics? OK for me, but you need to handle one.

The grip is oversized to make room for the tall .357 Magnum, so I strongly advise handling one instead of buying sight unseen.

For me, it was just on the edge of what I can work with. I passed on an AMT Auto Mag in 45 Winchester Magnum, because it was a bit too big for my hand. Desert Eagle grips are far too big for me. Fortunately the .357 Magnum is 0.04″ thinner than the 45 ACP at the base. Even with the lengthening, the handle stayed slim enough to get a solid hold with two hands. I don’t notice that the Coonan feels bad in the hand, but I do notice that picking up a 1911 in 45 ACP after shooting the Coonan feels so much better.

I spent a lot of time filing off the “memory groove” on the aftermarket beavertail I installed. It made the grip on the Coonan too thick for me, although the same beavertail feels nice in a standard 1911.

Bottom line: This is the most fun range toy I have.

No gun gets as much attention at the range as my Coonan. Flashy handholds with H110 are a blast. I can also run mild target wadcutters, although I’m still fine-tuning different springs and loads to get them to cycle. I’m still working on unlocking the full potential of the 38 caliber bullets on the market. They offer better sectional density and ballistic coefficients than what I can safely put in a 45 ACP. I’m starting to doubt I’ll ever see a practical difference, but it sure is fun to try!

Notes on gas-ring streaching

It’s hard. But still go slow. You can go too far!

Consider ordering a single hardened plug gauge from amazon instead of the spindle. The spindle got crushed when I went to far. I was surprised but happy to find that Amazon sold individual plug gauges.

Use grease on the spindle. I used cutting oil, but it still galled.

357 Magnum + 170gr Sierra #8350

The 170gr Sierra #8350 jacketed round-nose gives me confidence because it looks like it has a good BC, would feed in an automatic, and has very little weight variation (Sierra makes a good bullet!). Sectional Density 0.191, Ballistic Coefficients

  • .175 @ 1300 fps and above
  • .285 between 1300 and 900 fps
  • .222 @ 900 fps and below

Cartridge: 357 Magnum

Brass: Starline

Primer: WSPM

Cartridge Length: 1.585″.

Bullet: 170gr Sierra #8350, FMJ RN

Powder: H110

Series 49=14gr H110: 1148fps avg, ES 43, StdDev 14(7x) (1171, 1144, 1155, 1128, 1136, 1153, 1150)

Series 50=14.5gr H110: 1173fps avg, ES 71.5, StdDev 26.21(8x) (1211, 1151, 1202, 1146, 1179, 1140, 1171, 1186)

Both cycled the Coonan well, with full-power spring and flat firing-pin-stop.