.357 Maximum

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MIshooter

Single-Sixer
Joined
Apr 10, 2006
Messages
276
Location
Michigan
A bit of an unusual happening this weekend I'm at a loss to explain and hope maybe someone here can explain.

Some background on the gun and ammo. Rifle is a custom Ruger No. 1 using a 1-16 twist stainless Shilen barrel, 24" length. Scope is a 2.5-5x Leupold Vari X III. Velocities were measured with a Chrony instrument places 10' in front of the muzzle. Ammo was made in Starline new brass, Hornady 200 gr RN, Rem 7 1/2 primers and powder was IMR 4227 and RE-7.

I took the loads from Hornady 7th edition for a 10" TC Contender. Charge #1 was 18.0 gr IMR 4227 with a velocity shown for the TC as 1450 fps. Charge #2 was 25.0 gr RE-7 for a TC velocity of 1550 fps.

Now the mystery......

Chrony velocity data for RE-7 was average 1815 fps for 6 shots or a velocity INCREASE of 265 fps. But, when I ran the IMR 4227 load the velocity was only 1410 fps or roughly 40 fps BELOW the 10" TC data.

What?? That's a first for me where 24" data was below 10" data. Before you wonder on charge weights, each load was hand weighed and the scale confirmed prior to throwing charges.

Ideas? Comments?
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
25,142
Location
Lake Lure NC USA
Ok, I'm assuming you meant RL-7 for load #2.

If so,, IMR-4227 is a faster burning powder,,, than RL-7. And as such,, it's POSSIBLE that the 4227 passed it's peak burn in the barrel and the heavy bullet slowed down a bit as compared to the RL-7.
Next,, your data,, using manual #7 instead of a current one,, isn't always advisable.
And,, your data,, the Hornady books,, the information was for the 10" Contender,,,and you put that ammo in a rifle bbl. That's ALMOST 2-1/2 times longer than the Contender bbl used in the Hornady information.
I'd suggest you look at slower burning powders,, with rifle primers,, and work with that type of data.

I suspect your issues are with the barrel length,, combined with using pistol data.
 

MIshooter

Single-Sixer
Joined
Apr 10, 2006
Messages
276
Location
Michigan
Contender
Yes Reloader 7.

Hornady #10 shows same RL-7 loads, just omits IMR-4227 data and adds Lil Gun data.

Rem 7 1/2 are small rifle BR primers.

I had done some previous loads with a Hornady 180 gr XTP and used the same powder and got increases in velocity with both powders which is why the 200 gr results baffle me.

This should be close to a 350 Legend data wise if it was available. Unfortunately, rifle data with a 357 Max from the major manufactures does not exist so working with TC data is the only starting point. My next step will likely be Lil Gun.

Thanks for the input.

MIshooter
 

sixshot

Buckeye
Joined
Aug 20, 2006
Messages
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Location
soda springs, idaho
Yes the Rem 7 1/2 is a HOT small rifle primer, one of the hottest, that's why we use them in the maximum. The only other primer that gets used in the maximum is the CCI 450 which is also a magnum small rifle primer. You might try that one with both loads just to compare against your 180 gr load velocities.

As for the big slow down with 4227 it could have something to do with that long bearing surface of the 200 gr RN but that seems like a lot of velocity loss to me. If you don' get some change after trying the other primers you "might" try some 4198 SC (short cut) but I doubt you're going to see much improvement, if any. RL 7 might be your sweet spot in that long tube.

Dick
 

contender

Ruger Guru
Joined
Sep 18, 2002
Messages
25,142
Location
Lake Lure NC USA
My mistake on the primers. I didn't look them up,, and I don't use Remington primers because they aren't available locally to me.

I have used the 180 Hornadys,, and tried the 200 grn ones as well. But my guns are both Contenders & Rugers. My Contender bbls are 10" & 14". I didn't have my data easily available to me,, as I haven't fooled with those jacketed bullets in a long time. I tried to use the 200 grn Hornady's in my Contenders a long time ago,, and just couldn't get the accuracy I desired. I got much better accuracy with the 180's. I'd have to check my notebook to see if I got much velocity differences,, but I don't recall a drop in it when switching between the 10" & the 14" Bbls.

I mentioned the bbl length,, as I did look up the loads & you are close to the max charges for both if my sleepy memory is correct.
Sixshot may be onto something with the bearing surface issue,, (kinda goes with my thoughts on the burn time,) as well as trying 4198 SC as well. But the RL-7 may well be the better powder to try using.

Looking up other rifle data,, using 357 Magnum as a base,, and the Hornady 180 grn XTP's,, with IMR 4227,, a max charge is 12.3 grns,, with a published velocity of 1200 fps. They used a Rossi 16" bbl with a 1-16" twist. The 10" T/C bbl in the Maxi shows 19.0 grns with a velocity of 1550 fps as a max charge.
And looking at other data for rifle calibers,, using the same 200 grn .358 bullet,,, I do see RL-7 listed as the fastest powder & starting powder.

Delving into the mysteries of reloading is always fun,, as long as it's done safely. Maybe a call to a couple of the companies Tech depts may offer some insight???????
 

Shaggy357

Bearcat
Joined
Apr 5, 2017
Messages
26
RL-7 will burn and accelerate the bullet for the duration of rifle barrel travel. Out of the 10" Contender barrel, you would likely have unburned powder. IMR 4227 is much faster. The pressure peak was reached when the bullet was only partially down the barrel. As pressure decreases due to the expanding volume, the bullet already starts to slow down.

Loads for 10" Contender barrels do not usually work well in rifle barrels. Significant variation can be seen even when going from 10" Contender barrel to 14" Contender barrel.
 

dgr416

Single-Sixer
Joined
Jan 4, 2008
Messages
179
Location
Georgia
Try aa1680 powder it's awesome in the 357 rem max.I loaded over 10000rounds with it .It is awesome in my tc carbine in contender and encore
 
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