Author Topic: Uberti Baby RB and .357 Rem Maximum (Read 4516 times)

Uberti · « **on:** January 13, 2011, 08:19:47 AM »

Hello all GBO enthusiasts.

I have a Uberti Baby RB in .357 mag that I`m about to re-chamber to .357 Rem Max. Wondering, have any of you done this? I have researched this topic on other sites, and even asked Uberti USA, and I have yet to find anyone who has done this conversion.

Is the Uberti up to the pressure increase?? Well, my chief rationale for choosing to go ahead with the conversion, is the fact that Uberti offered the exact same carbine as mine in 5.6 x 50 R mag., which has a higher pressure rating than does the .357 mag cartidge.
http://www.ubertireplicas.com/lever-babyrollingcar.php
http://kwk.us/pressures.html

Further, the case diameters are almost the same dimensions.
http://stevespages.com/page8d.htm

I shoot 180gr Cast Performance bullets and will be staying with these pills for the .357 Rem Max loading. My goal is to target 2000 fps, and then work on accuracy from that approximate velocity.
I realize many others loading the same weight boolits for single shot .357 Rem Max achieve more veloctiy than 2000fps, but because this is STILL a .357 mag rifle, I wish to remain on the side of caution. Not looking for an early dirt nap, lol.

I ve been trying to wade through the PSI, CIP, CUP pressure differences and theories of why-fors, converting PSI pressures to CUP, etc, etc, on the .357 Rem max and the .357 mag loadings, and the info has me going around in circles. This combined with fact that published reloading info from the powder manufactures and bullet manuals do not include pressure ratings for the Rem Max loads??

The 180 gr load I shoot now in .357 mag Uberti , 14.9 gr H110 is not too far off my target of 2000fps, but I would still like to see some published info on the pressures that others like Cor bon and Buffalo Bore 180gr loads are reaching, but they don`t list the pressures.

One more question...... what is the CIP rating for .357 mag cartidge? For Italian guns specifically? I read that Pedersoli proof tests their guns at 30 percent greater than PMax pressures
http://www.bpcr.net/index-a.htm but, Pedersoli is not Uberti.......will Uberti use the same PMax pressures that Pedersoili uses? I see that it is 46411 CUP-PSI for the .357 mag.

Thanks for your thoughts!

Uberti · « **Reply #1 on:** January 19, 2011, 05:57:22 AM »

Hummmmm. Nobody wants to play??

Certainly there are other .357 max enthusiasts that wish to discuss topics such as .357 max conversions, .357 max pressures, and which powders are the most efficient for this cartridge and bullet weight..........

quickdtoo · « **Reply #2 on:** January 19, 2011, 06:26:48 AM »

Welcome to GBO! Lots of 357Maxi conversions in the H&R forum, I even rent a reamer to encourage em, see the sticky there!

FWIW, Quickload software lists the 357mag as 43511PSI(CIP) and the 357Maxi as 44962 PSI(CIP). Can't help ya with the strength of the Uberti other than what I already offered at Shooters Forum on the 5.6x50R.

Tim

http://www.gboreloaded.com/forums/index.php/board,126.0.html

Uberti · « **Reply #3 on:** January 19, 2011, 12:39:45 PM »

Hey Tim,
Thanks for the reply, and for the Quickload specs.
Yes, the reamer rental is a great idea. I wanted a slightly modified .357 maxi reamer, carbine specific, and so ordered one from Dave Manson. Just waiting for it to arrive.
Was at the range today with the new F1 Chrony, and I tested the .357 magnum loads that I have been shooting, so I have a baseline, so to speak, before I ream the chamber and work on a maxi load.

180gr Cast Performance bullets over 14.9gr of H110, Fed small pistol primer, in the 22 inch carbine was between 1550 to 1623 fps.
I can see I have a ways to go with the conversion maxi load in order to see 2000fps that I`m hoping for.

quickdtoo · « **Reply #4 on:** January 19, 2011, 02:31:52 PM »

Best of luck with it, sounds like a nice project, my reamer is a PTG rifle reamer, it's cut over 50 chambers so far, most by hand, no complaints at all from anyone shooting 38 spcl, 357mag or 357 Maxi.

Tim

Uberti · « **Reply #5 on:** January 19, 2011, 05:22:30 PM »

That`s one thing I`ve been wondering about........... shooting 38 special cartidges in the .357 maxi chamber. What will the accuracy be like, with the bullet being so far off the lands?

quickdtoo · « **Reply #6 on:** January 19, 2011, 05:56:45 PM »

Read some of the reports in the H&R forum, there's hundreds of em, like I said, no complaints on any of the shorter rounds, forgot about the 360 Dan Wesson.

Tim

Kmrere42 · « **Reply #7 on:** January 24, 2011, 04:29:36 PM »

HEY ....!!!!!!!!! ........

Hold on just for a moment, Sorry for YELLING at you.... !!!!!!!!!!!

The NEF SB2 is rated for chamber pressures that the Max will develop and then some.

That neat little rolling block just might not be able to take that kind of pressure and if it lets go, it will embed pieces of the block in you forehead....

The NEF has a standing breach supported by two sidewalls. The rolling-block depends on a pair of pins and the strength of the block itself. And while the NEF will pop open with an overload, it just is not as catastrophic as the rolling-block opening up.

Saami pressures are,

357 Mag, 35,000 CUP. (1995)

357 MAX, 48,000 CUP

PLEASE be very thoughtful before you ream it out to the max..

This is the one rifle design excepting the old 44's that I would be really careful of, If indeed that the rifle is proofed for the full 46k rating then consider it.

Paul

quickdtoo · « **Reply #8 on:** January 24, 2011, 07:15:46 PM »

Paul,

The SAAMI MAP for the 357Mag is 35kpsi, not CUP, and the 357Maximum is 40kpsi. And I already posted an apples to apples pressure comparison for the two in the CIP standard (357mag=43511PSI(CIP) & 357Maxi=44962 PSI(CIP)). to compare to 5.6x50R which operates at 49kpsi(CIP) which the Uberti is also factory chambered in which has a similar size case head to the 357Maximum and slightly higher pressure. Since the Baby Uberti is available in 5.6x50R and uses the same frame according to the Uberti parts list, http://www.ubertireplicas.com/tecniche/rifles_carbines/rollingblockbabycarbine375mag.php it should work just fine.

Bolt(breech) thrust is a simple calculation to make. http://www.riflebarrels.com/articles/custom_actions/bolt_lug_strength.htm You can use Pressure x Area = Force, all you need to do is to calculate the area of the case head X Chamber pressure for a rough estimate, although Lilja uses the inside case head area.

And BTW, H&R(there is no NEF any more) has offered the 357Mag (and 44Mag) on cast iron SB1 shotgun frames for over 3yrs now, which work fine rechambered to Maximum, they quit offering them with SB2 frames in late 2007.

Tim

http://www.lasc.us/SAAMIMaxPressure.htm

http://www.handloads.com/misc/saami.htm

5.6x50R

Uberti · « **Reply #9 on:** February 27, 2011, 03:05:50 PM »

Tim,
Thanks for posting all of the info relevant to the Uberti .357 mag to .357 max conversion I am doing.

I have received the .357 max reamer from Dave Manson, and have reamed the chamber out with no difficulties. It went well, as I went slowly and was sure to withdrawl and clean the reamer of metal chips after every few turns.

The .357 max dummy round that I made up chambers easily, however, the bullet does need to be crimped into the crimp groove, as I discovered by trying to leave more leade, the round would not chamber......it was too long to get over the rolling blocks. So, the crimp groove it is............

quickdtoo · « **Reply #10 on:** February 27, 2011, 05:15:39 PM »

Range report is expected!!

Tim

S.E.Ak · « **Reply #11 on:** March 02, 2011, 08:58:52 AM »

What Tim said. My brides 357max shoots 38spec about as well as the max and the 357mag does shoot as well as the max

kiddekop · « **Reply #12 on:** March 24, 2011, 07:57:56 AM »

I had a tc encore in remington 260 I purchased for deer and elk hunting after a couple of back surgeries and walking around w/o any cartilage in my right knee however my errant son paid me a visit and probably left with the rifle when I wasn't looking taking the newly reloaded brass.I contacted Bullberry Barrel Works to make me a 20" SS Encore barrel in 454 casull but when the S&W 460 mag appeared I sent the barrel back to Bullberry to be rechambered.A week ago I went to the range to try it out with hornaday 460 ammo , it has some really serious recoil,then I fired some corbon 454 casull ammo which was a little bit better to shoot w/o as much recoil & finally I loaded some 45colt cowboy loads in it which was really easy shooting.

crossfire · « **Reply #13 on:** April 27, 2011, 10:40:17 PM »

If H110 doesn't get you what you want, try AA1680. It's actually a bit slow but it will develop 2200 fps in a 23" barrel Contender Carbine with the Hornady 180gr SSP. Use a magnum small rifle primer. If you are willing to change your bullets, I'd suggest 17.5-19.0gr IMR 4227 with a Lyman #358627 215gr SWC.

Steve E · « **Reply #14 on:** June 20, 2011, 01:39:21 PM »

Uberti

I have the same rifle and have been interested in the conversion for some time. How is yours doing so far? Have you tried Lil'Gun yet, it works fantastic in the 357 Maxi Encore barrel I have.

Steve E...............

Uberti · « **Reply #15 on:** September 26, 2011, 01:16:46 PM »

Steve,
I got side tracked with other obligations for a while, but have since loaded up a bunch of varying H110 powder loads that I will take to the range to try.

I have also bought a chronograph, and so the plan is to find the .357 max load that gives me the same velocity as does the 180gr .357 mag load that I shoot now, which turns out to average 1568 fps, and then slowly work up from there.......hoping to safely go to 1900 to 2000fps velocity, and then seek optimum accuracy in that range.

Have you done the conversion on your baby RB yet?
What is the bullet- Lil`gun load that works for your Encore?

Uberti · « **Reply #16 on:** September 27, 2011, 06:01:30 PM »

Finally got to burn some powder!
Here are the chronographed results of my Remington Maximum hanloads. Keep in mind, these loads were meant to test these uncharted waters of the now reamed out Uberti Baby Rolling Block .357 mag to .357 Max.

.357 Max Federal cases
H110 powder
Federal primers
180gr hard cast gas checked bullets

15gr 1669
16gr 1649 1639 1652
17gr 863.8 1681 1767
17.5gr 1811 1786 1836
18gr 1860 1812 1852
18.5gr 1903 1872 1887
19gr 1927 1946 1902
19.3gr 1936 1928 1897
19.6gr 2111 1946 1965
19.9gr 2016 1951 1964

The best 3 shot group at 25m with open sights......and a 3 shot group doesn`t mean much..... was 18gr. I could cover the group with a dime. The next best group was 19.9gr with 3 shots into 2 holes, 5mm apart.

No signs of excess pressure on the fired cases, the Uberti action functioned well....no hiccups. I may just load up some more 18gr loads and hunt with 180 grains at 1850 fps and not push the Uberti for the extra 100fps that almost 2gr gives. I doubt the critters I hunt will notice 100fps less inside 50m.

Uberti · « **Reply #17 on:** September 28, 2011, 05:05:29 PM »

Today I loaded up more rounds with 18gr of H110.
Off to the range.......
7 shot group at 25m......5 holes I could cover with a 25 cent piece, the 6th shot was about .5 inches away and the 7th hole was about .75 inches away from the quarter.
That`ll do.

Steve E · « **Reply #18 on:** September 28, 2011, 06:34:40 PM »

The bullet I am using is a Lee 180 grain gas check flat point from a group buy on one of the cast bullet forums. Now all this has got me wanting to do mine now.

Steve E............

yosemite · « **Reply #19 on:** October 01, 2011, 06:03:51 PM »

I think the biggest problem you may have is reloadability, all RB rifles have spring back in the action, just the nature of the design, all the smokeless powder rb OE rifles I habd "bent the case head with warmer loads, way below the pressure threshold , any primer cratering etc, the case then tilts in the shell holder and upon resizing binds and either crushes slightly or stretches, most for my 7mm would not chamber after reloading. you may have noticed the problem with hotter 357 loads already. this is not a given, but a possibility, keep the chamber clean and dry so the cartridge can grip the walls, I shoot 357 Max in a D Wesson supermag, it likes dry chambers too, one thing about it, you can always load to std 357 velocity at much lower pressure, Good luck!

Uberti · « **Reply #20 on:** October 02, 2011, 08:12:39 AM »

yosemite,
That is good insight and experince that you have shared, thanks. I will keep this in mind if I discover any problems with reloading the hotter 1 x fired cases. I have yet to reload any of the cases that I used for the .357 max load testing. Good thought on the advantage of having a dry chamber too.

I`m thinking that my load of 18gr of H110 with a 180gr bullet at 1830 fps is well below the maximum pressure of what the maximum cartridge is capeable of. Wether the pressure is below the the limit that may cause the case-head stretch in my Uberti that you describe is yet to be determined.

I plan to shoot this load only for hunting purposes........and so a whole year may go by without a hunting shot fired

. For plinking, I`d much rather use a light .357 mag load or even .38 sp. loads.

MSP Ret · « **Reply #21 on:** October 16, 2011, 03:00:05 PM »

Very interesting thread and thanks for the info. I have a H&R Handi Rifle in .357 Max which is a great gun and just picked up a Uberti baby rolling block in .357 Mag from a friend to keep for a few months and to try. I am already smitten with it's size and light weight. If all goes well I may be able to purchase it from him when he returns early next summer. It is mine to care for and shoot until then. I also have a Savage 24 in .357 Mag over 20 guage which I would like to lengthen to .357 Max but first have to work on the sights. With the rear irons all the way up it is still about 6" low at 50 yards. The good news is that .38's and 20 gauge slugs have the same POI at 50 yards. If I can get .357 Mags and 20 guage slugs centered on the bull at 50 yards it should make a nice gun....<><....