Best LEE mold for ROSSI '92 .357mag

[LynC2]

What is an "NRA Chambering reamer"??

This post from Ed Harris on Handloads.com explains better than I.
"The usual .357 Magnum rifle chamber resembles the same form used in the SAAMI pressure test barrel. That is simply a 15-degree included angle forcing cone which departs directly from the cylindrical .379 diameter at the case mouth, with no "ball seat."

Testing was published by the NRA in the 1980s in which T/C Contender handguns and Marlin 1894 rifles were rethroated, using a more gradual 3 degree forcing cone. This reamer followed the form of automatic match pistols produced by the US Army Marksmanship Unit (AMU) which were chambered for .38 Special wadcutter ammunition. The ".38 AMU style" chamber throat put on a .357 Magnum-length reamer improved accuracy dramatically, reducing long run average group size by 25-50%.

You can buy the ".357 NRA" chambering reamer with this throating from JGS Guntools. It is a custom design which is made to order and cost is about $165 last time I checked. It is easy to re-cut the chamber throat of .357 Magnum rifles by hand to correct "problem" shooters."

[Nobade]

I wonder how this would work, since the common complaint with 357 rifles is the throat is too long and by the time you touch it with a boolit, said boolit is no longer in the case. I would like to see a drawing of that reamer. All factory made 357 rifles I have ever seen had a very gradual forcing cone style throat with no clear end to the chamber. Maybe they are making them like that NRA style chamber now anyway?

-Nobade

[LynC2]

I wonder how this would work, since the common complaint with 357 rifles is the throat is too long and by the time you touch it with a boolit, said boolit is no longer in the case. I would like to see a drawing of that reamer. All factory made 357 rifles I have ever seen had a very gradual forcing cone style throat with no clear end to the chamber. Maybe they are making them like that NRA style chamber now anyway?

-Nobade

That is an interesting tidbit and hopefully they are using that type of reamer now. I have chambered a lot of barrels but mostly for High Power and 1000yd shooting. .357 Mags are uncharted waters for me. Anyway yesterday I requested a reamer print from Pacific Tool & Gauge if they had one for it. When I do a chamber & throat cast I'll have a better idea of what my Rossi 92 looks like.

[fecmech]

Lynn-Here are 3 impact castings from my 3 rifles. Left one is Winchester 94, next Rossi 92 carbine and on the right Rossi 92 Octagon rifle. The winchester throat is an abomination in that it is .400" long and is a fight to keep from leading. Rossi's seem to be your basic "toilet bowl" throat. A machinist friend is going to bush my 94 chamber and I am very much interested in a reamer that would give me a throat found in regular rifles where there is a step where the case ends. In the 94 I would end up with some freebore but I think that's much less of a problem than what I have. I'm wondering if I can rent such a reamer.

Maybe they are making them like that NRA style chamber now anyway?

Not to my knowlege. Both of my Rossi's are current Braztec Rossi's.

[Nobade]

Perfect paper patch chambers! Too bad the ammo ends up way too long to work through the magazine. Shoots good that way though.

The Ranch Dog 175 is designed just for this sort of chamber. Real fat nose that lets it engage the rifling and fit in the magazine at the same time. Lots of guys also get very good accuracy with the RCBS 200gr. rifle boolit seated to just work through the mag.

-Nobade

[LynC2]

Lynn-Here are 3 impact castings from my 3 rifles. Left one is Winchester 94, next Rossi 92 carbine and on the right Rossi 92 Octagon rifle. The winchester throat is an abomination in that it is .400" long and is a fight to keep from leading. Rossi's seem to be your basic "toilet bowl" throat. A machinist friend is going to bush my 94 chamber and I am very much interested in a reamer that would give me a throat found in regular rifles where there is a step where the case ends. In the 94 I would end up with some freebore but I think that's much less of a problem than what I have. I'm wondering if I can rent such a reamer.

Not to my knowlege. Both of my Rossi's are current Braztec Rossi's.

I just did a cerrosafe cast of my 92 octagon bbl. It looks like yours, a tapered transition of approximately .170 in length so I see no way to do anything about it other than setting the barrel back or re-barreling. BTW, the bore measures .3572"
As Nobade mentioned that when the bullet is seated out to engrave the rifling it becomes too long to feed through the action which I discovered very quickly. I guess the best option would to get a custom mold for a 'fat" boolit. I doubt there is a rental reamer available that would be what we would want. It most likely would be a custom ground one from one of the manufacturers. RATS!

Edited to add: It looks like the "ball seat" is the problem and that Win chamber ball seat makes the Rossi look reasonable by comparison!

[LynC2]

Perfect paper patch chambers! Too bad the ammo ends up way too long to work through the magazine. Shoots good that way though.

The Ranch Dog 175 is designed just for this sort of chamber. Real fat nose that lets it engage the rifling and fit in the magazine at the same time. Lots of guys also get very good accuracy with the RCBS 200gr. rifle boolit seated to just work through the mag.

-Nobade

Nobade, are these guys getting good accuracy in the Rossi with those heavy boolits? The twist rate looks like anything above a 158 or 160 would be about tops.

[Nobade]

Not the Rossi, but rather the Marlin. I am not personally familiar with anybody shooting a Rossi at anything more than CAS distances. You get to be the test subject! What is the twist in that barrel? I wonder just how big a boolit it can handle.

-Nobade

[LynC2]

Not the Rossi, but rather the Marlin. I am not personally familiar with anybody shooting a Rossi at anything more than CAS distances. You get to be the test subject! What is the twist in that barrel? I wonder just how big a boolit it can handle.

-Nobade

OK, that is what I thought. It is the usual slow 1x30", so finding a bullet that is fat and long enough to engrave the rifling (most likely just close) but still doesn't weigh too much to stabilize yet still feed through the magazine is going to be a problem. The typical long ball seat does seem to be the major issue with most .357 rifles. If they didn't have that transition and had a chamber as described as a NRA reamer chamber it wouldn't be an issue.

[LynC2]

Sorry, did a double.

[LynC2]

My apologies to the OP, derek45. It seems his Lee bullet mold thread morphed and was hijacked a couple of pages ago.
To get back on track I will say I have a couple of Lee molds to try and just ordered a Lee 6-Cavity Bullet Mold 358-150-1R to try. I suspect it is close to the upper limit of weight that will stabilize at 200 yds.

[fecmech]

Lynn--The Lee TL SWC 158 seems to work pretty well at around 1100 fps out of both my Rossi's. While it is no tack driver it will shoot 3-4 moa at 200 yds. Holes in the paper at that range are round. The RCBS 9MM 124 cn shoots a little better and what I use for our 100 yd silhouette. I run that about 1250 fps for all the targets except the rams. I use the TL 158 for them. I have had no luck at all with the Lee 158 RNFP,H&G 158 rn or the NOE 180 FP at subsonic velocities. The NOE did not shoot at 1500fps for me either. When you get that mold if you'd like to swap some bullets I'd like to try some of those for some TL SWC's or any thing else I have.

[1Shirt]

The 158 RNFN is a good one, but don't overlook the little 124 RNFN as well. It is accurate, feeds well, and saves lead if you want a good second blt.
1Shirt!

[LynC2]

Lynn--The Lee TL SWC 158 seems to work pretty well at around 1100 fps out of both my Rossi's. While it is no tack driver it will shoot 3-4 moa at 200 yds. Holes in the paper at that range are round. The RCBS 9MM 124 cn shoots a little better and what I use for our 100 yd silhouette. I run that about 1250 fps for all the targets except the rams. I use the TL 158 for them. I have had no luck at all with the Lee 158 RNFP,H&G 158 rn or the NOE 180 FP at subsonic velocities. The NOE did not shoot at 1500fps for me either. When you get that mold if you'd like to swap some bullets I'd like to try some of those for some TL SWC's or any thing else I have.

Thanks for the update, I'll keep that all in mind if the others don't work. Give me a bit of time to play with this and we'll do a bullet swap.

[LynC2]

The 158 RNFN is a good one, but don't overlook the little 124 RNFN as well. It is accurate, feeds well, and saves lead if you want a good second blt.
1Shirt!

Thanks for that information; one needs all the workable options on these to find something useful.

[BuckRimfire]

It's designed for a Lee Rifle Crimp die, which works great on lead and no crimp groove. ]

Which rifle FCD works with the .357 case? I understand that the .44-40 fits .44 Mags with a little work, but I can't see a match for .357, except .35 Rem and an extended case holder?

[357shooter]

Which rifle FCD works with the .357 case? I understand that the .44-40 fits .44 Mags with a little work, but I can't see a match for .357, except .35 Rem and an extended case holder?

Lee custom makes one specifically for 357 mag. Sometimes they have them in stock.

Try this link: http://leeprecision.com/357-mag-cust...crimp-die.html

[jmort]

They do right now, I just got two. Also .41 and .44 mag in stock as well.

[TCLouis]

I have been shooting the 160 grain RNFP GB boolit in 38 SPL cases over 4.1 and 4.6 of Promo (THIS IS NOT A LOAD RECOMMENDATION BY THE WAY). 4.9 grains is past the limit somewhat by the way. These are made up in nickle cases because at my house nickle cases are for 357 chambered guns only no matter whether they are 357 or 38 SPL..
QL says 11,00 fps.

Accurate 1.5 X 1.5" at 50 and still able to break the rocks (4 - 6") on the hillside above my range at about 110 yards.

[MT Gianni]

TCLouis, what is the OAL of those? Thanks.