.357 Magnum from lever rifle 20" barrel

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Morne
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.357 Magnum from lever rifle 20" barrel

Post by Morne »

I was looking over my handload data for .357 Magnum recipes I had worked up and realized that up until now ALL of my data was from a 6" barrel. Now that's not a bad thing, the .357 Magnum rather likes a 6" barrel, but it also doesn't tell me how the rounds might perform in a lever action rifle platform. So I got the Rossi M92 with a 20" barrel out of the safe and set out to chrono some of these loads (5-shot strings all):

***CHRONY DATA***

69 F, 30.08" Hg, 95%RH

.357 Magnum 158-gr CPSWC @1.600" COAL
Rossi M92 with 20" barrel

16.0-gr Lil'Gun powder CCI-500SPP - AVERAGE = 1913 fps - ES = 49
16.0-gr Lil'Gun powder CCI-550SPP(m) - AVERAGE = 1785 fps - ES = 88
16.8-gr Lil'Gun powder CCI-550SPP(m) - AVERAGE = 1778 fps - ES = 65

.357 Magnum 125-gr CPHP @1.575" COAL
Rossi M92 with 20" barrel

16.5-gr Ramshot Enforcer powder WSP(m) - AVERAGE = 1955 fps - ES = 79
8.2-gr W-231 powder CCI-500SPP - AVERAGE = 1574 fps - ES = 94

The 125-gr CPHP did not want to feed well in my Rossi M92. :evil:

Ironically the lower charge weight of Lil'Gun with the non-magnum primer gave both the best velocity and the tightest ES in the 158-gr CPSWC trial. 8)

Also, they did leave a slight mark on my shoulder. The metal buttplate on my rifle is not ergonomic, yo... :P

At the end of the day a 158-gr slug travelling close to 2000 fps is serious business. That is very similar to the weight and muzzle velocity of some of my .300 AAC Blackout loads.
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Re: .357 Magnum from lever rifle 20" barrel

Post by Sevens »

It's often been said (and in my findings... usually close to "right on") that you can usually expect 300-400 fps increase in .357 Mag from a 6-inch revolver to an 18-20" carbine. You have two big gains... lots of tube to burn the powder and sealed with no flash-gap or jump from cylinder to forcing cone.

Published load data is typically exactly the same powder charge but usually lists a higher expected velocity with a carbine, but make no mistake, a slower powder truly shine with the longer barrel. And while it is known that I am a card carrying Lil'Gun HATER, a carbine .357 is a fantastic place for this powder. Recall I supplied you with your Lil'Gun ;) and now that I own a Ruger 77/357, I actually have a platform where I would choose to use it.

But no worries, I've got lots of slow burners. I've been running a cast and powder coated 180gr slug in that rifle using AA#9 (I think...?) and it's giving me a consistent 1,500fps with zero signs of excess pressure. The rifle is a little sweetheart and only needs some improvement in the trigger.

For the loads you posted... I'm curious if those plated bullets hold up to the pure abuse of that velocity. Seems to be outside the scope of their design. You'd find erratic accuracy and extra slivers, holes and slashes in a paper target if they were coming apart in flight. I don't believe there is any "safety risk", so if it's only about slapping steel or paper and they are accurate, I'd keep running them. Definitely not for any hunting.
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum from lever rifle 20" barrel

Post by Morne »

These were all X-Treme plated Bullets.

Just ringing steel. For social or hunting needs I have factory stuff.
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Re: .357 Magnum from lever rifle 20" barrel

Post by willbird »

The older Rossi have 1:16 twist, the newer ones from what I am reading are all 1:30 no matter the caliber.

The 1:30 might not like 180 grain bullets.

I was wondering if it might not hit the same velocity with a 180 as it did with the lighter bullets.
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Re: .357 Magnum from lever rifle 20" barrel

Post by Morne »

***CHRONY DATA***

63 F, 30.01" Hg, 62%RH

.357 Magnum 180-gr Hornady XTP 1.580-1.587" COAL CCI-550SPP(m)
Rossi M92 with 20" barrel

13.0-gr Lil'Gun powder AVERAGE = 1470 fps - ES = 75
13.6-gr Lil'Gun powder AVERAGE = 1458 fps - ES = 84
14.2-gr Lil'Gun powder AVERAGE = 1449 fps - ES = 61
14.8-gr (1.0cc) Lil'Gun powder AVERAGE = 1471 fps - ES = 50

10.0-gr (0.7cc) Ramshot Enforcer powder AVERAGE = 1031 fps - ES = 118.2

The Lil'Gun loads were essentially independent of the actual weight of powder used. Having said that, the highest weight, which was easiest to dispense using a 1.0cc dipper, had the tightest ES. Anything north of 1400 fps is good for this hunting bullet according to what I have read.

I could try working up more of a ladder with the Ramshot Enforcer, as this one rung was way too light, but frankly with such a good option from Lil'Gun I just don't see any reason to bother.
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Re: .357 Magnum from lever rifle 20" barrel

Post by Sevens »

I look at what you posted and what jumps off the page is that your top and bottom Lil'Gun loads post the same average velocity. That's a 13% increase in powder charge with the SAME velocity.

That would make me want to test those two loads again and again and see if the results are consistent and see what accuracy you get in comparison.
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum from lever rifle 20" barrel

Post by Morne »

If these were inexpensive bullets I would be willing to retest them again & again. But Hornady 180-Gr XTP are not cheap.
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Re: .357 Magnum from lever rifle 20" barrel

Post by willbird »

Sevens wrote:I look at what you posted and what jumps off the page is that your top and bottom Lil'Gun loads post the same average velocity. That's a 13% increase in powder charge with the SAME velocity.

That would make me want to test those two loads again and again and see if the results are consistent and see what accuracy you get in comparison.
There is a "dude" out on the web that refers to himself as "the overloader". He takes published data and loads hotter than that, sometimes quite a bit hotter. He did that with 357 LilGun loads and with each increase in powder charge he got more recoil and no signs of high pressure. He was able to use quite a bit more LilGun.

At a later date he did a crono test on his largest powder charges of LilGun in 357 and found that the increase in charge weight did not increase velocity, it did increase recoil because the powder weight is part of the "ejecta" whether it is ejected as unburned powder or powder gas.

Exited he wrote an email to Hodgdon telling them of his discovery, they replied "we know, that is why we listed the maximum load as xx grains, adding any more does not increase velocity.:-).

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Re: .357 Magnum from lever rifle 20" barrel

Post by AlanM »

Makes sense to me. I agree.

I would expect a larger visible muzzle flash, but I don't know much about how much unburnt powder is typically expelled.

My SWAG would be to load such that the pressure in the barrel is constant or increasing up until the projectile exits the barrel. That is minimum ejecta.
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Re: .357 Magnum from lever rifle 20" barrel

Post by willbird »

AlanM wrote:Makes sense to me. I agree.

I would expect a larger visible muzzle flash, but I don't know much about how much unburnt powder is typically expelled.

My SWAG would be to load such that the pressure in the barrel is constant or increasing up until the projectile exits the barrel. That is minimum ejecta.
The theory in my words is that the powder weight is ejected whether burned or unburned, it gets converted to a much larger volume of gas that still weighs as much as the original powder charge did. And all of that gas is expelled from the muzzle until the bore pressure has equalized with atmospheric pressure.



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Re: .357 Magnum from lever rifle 20" barrel

Post by Sevens »

Years ago I finally bought my first chronograph and I couldn't believe how long I had dragged my feet to do so... rolling my own for 20 years before buying my first ticker.

Well, beyond finding mildly interesting tidbits here and there, I've found that the "necessity" of a chronograph is just not there for me and as a side opinion-- wildly overrated by others.

However, two places where they definitely provide a good utility--
1) if you MUST make a minimum legal velocity, every time, no question, to maintain qualification in some shooting competition and you roll your own

2) estimating bullet drop for long distance shooting with rifles

Yesterday I was using my Ruger 77/357 to plink steel on the rifle range. Two things that made me smile... a .38 Special load sending a 158gr plated slug with 3.6gr Bullseye out of this rig with a rainbow trajectory to smack a quarter-sized IPSC plate at 200 yards... and the same rifle with a 180gr cast and PC'd slug powdered by a dose of AA#9 (12.0gr I think?) in to a 12" plate at 300 yards.

A chrono on these rounds well ahead of time could have saved me maybe 10 rounds of "walk in" shots between the two, but that wouldn't have been worth the hassle or annoyance associated with setting up and using my Chrony Master Beta.

A LabRadar is quicker, cleaner and easier but LOL at that money.
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum from lever rifle 20" barrel

Post by willbird »

Sevens wrote: 2) estimating bullet drop for long distance shooting with rifles

Yesterday I was using my Ruger 77/357 to plink steel on the rifle range. Two things that made me smile... a .38 Special load sending a 158gr plated slug with 3.6gr Bullseye out of this rig with a rainbow trajectory to smack a quarter-sized IPSC plate at 200 yards... and the same rifle with a 180gr cast and PC'd slug powdered by a dose of AA#9 (12.0gr I think?) in to a 12" plate at 300 yards.

A chrono on these rounds well ahead of time could have saved me maybe 10 rounds of "walk in" shots between the two, but that wouldn't have been worth the hassle or annoyance associated with setting up and using my Chrony Master Beta.

A LabRadar is quicker, cleaner and easier but LOL at that money.
The LaBRadar will actually give you a true BC number too...for stuff that has no published BC's. Honestly with inflation the LabRadar may be comparable in real price to what my Oehler 35P was when I bought it. I'll end up with a LabRadar one of these days :-).

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Re: .357 Magnum from lever rifle 20" barrel

Post by Sevens »

Bwahahaha, if you bought an Oehler in the 1980's then YES, the LabRadar is already cheaper! :D
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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Re: .357 Magnum from lever rifle 20" barrel

Post by OhioPaints »

I did some testing a while back with the polymer coated bullets and really loved them. They left the barrel sparkling clean. IIRC, I was getting around 2000 fps. They are cheaper than FMJ and about a penny more than lead bullets.

I will see if I fan find my notes.
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Re: .357 Magnum from lever rifle 20" barrel

Post by Sevens »

2000 fps?

110's or 125's?
I like to swap brass... and I'm looking for .32 H&R Mag, .327 Fed Mag, .380 Auto and 10mm. If you have some and would like to swap for something else, send me a note!
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