I just picked up a so close to new I can't believe it, 450M BLR...with two extra mags and a price that won't sink in for another day or two.

and....NOT ONE LOADED ROUND OR PIECE OF BRASS IN TOWN...GRRRRR

The following is for INFORMATION ONLY, NOT RECOMMENDED, DON'T DO IT...unless you know what the H*** is going on.

I've always wondered about using a regular old belted mag cases in the 450M and what was required to accomplish the task...SAFELY...I have a 45-70 barrel coming for my swap barrel Marlin project and was going to rechamber it to 450 M to see...for my own edification...now I can just rechamber to 45 Alaskan or to 45-90 to get a little more COAL.

I already have a 458 American and brass of several lengths so I grabbed one which happened to be a 416 Rem originally.

The case was 2.25" long so I started trimming it down and fitting it to the chamber knowing the chamber end was somewhere between 2.10", factory 450M length, and maybe 2.20" I would hit the end of the chamber somewhere...it turned out to be 2.15". The bolt just locked at that length.

I also measured 4 - 45 cal bullets, two 300 gr, one 350 gr and one 430 gr...AND the magazine max length...2.61" but 2.60" is much better for feeding.

Once I knew where the case was stopped by the chamber end and where the bullets touched, I could establish a COAL where the loaded round WOULDN'T move forward due to the 0.060" difference in headspace between a 450 M case, 0.280" and the 416 Rem, 0.220", later I changed to a 458 WM case trimmed to 2.145".

I quickly found out the wall thickness in the 416 made a bump in the case with the seated bullet and it wouldn't chamber until I resized out the bump. TOTAL PITA.

I check some Winchester 458 WM cases I had trimmed to 2.35" for the 458 A and the wall thickness taper that was causing the bump didn't start until just below end of the seated 350 gr bullet so I didn't have to resize those cases after reloading. I may have a problem with the much longer 430 gr TrueShot bullet, but that experiment is for another day.

I worked up loads with the 350 gr Hornady FP, I had 9 left, starting with 25 gr and working up to 30 gr RL-10X..velo ~1200fs, pressure unknown.

I crawled all over the net looking for data then found some in the 48th ed Lyman manual for Benchmark, it being slower than RL10X.

I started well down at 40 gr, working up to 50 gr Benchmark, COAL 2.61", velo 1676 fs in the 20" BLR barrel which matches closely the 1798 fs velo for the 24" universal barrel used in the Lyman manual...pressure ~31KCUP.

I stopped there. This experiment is just for "emergencies" anyway, and my 450 brass will be here in a few days.

There were NO problems associated with excess headspace that I could see or measure, no FTF's, the "0.060" excess headspace" was held to no more than maybe 0.010" by the case trimmed length AND the bullet into the lands... and the last case fired measured 0.5122" just in front of the belt...0.0006" larger than sized OD...that's about one third the amount that starts causing me the redazz in a belted mag case...31KCUP isn't moving the brass hardly at all.

This BLR will handle a LOT more pressure than a Marlin 1895M so for those who are worried about the 450 M brass drying up, this is a way to continue on for the next couple centuries.

I measured the barrel OD at 1.117" at the chamber, the 450 Marlin measures 0.512-0.513" just in front of the belt which means the chamber walls are ~0.329" thick...compare that to a Marlin 1895M...and that is one MASSIVE bolt compared with the Marlin bolt also.

NO DISS TO THE MARLIN...I LIKE MINE VERY WELL ALSO...

458 WM brass is plentiful, but the 350 RM might be better as the case length is already 2.17" and fireforming it might just leave you with the correct length...IF you can find that one also...

AGAIN...THIS IS FOR INFORMATIONAL PURPOSES ONLY...DON'T EVEN THINK ABOUT DOING IT UNLESS YOU FULLY UNDERSTAND WHAT HEADSPACE IS ALL ABOUT AND HOW TO WORK WITH IT...THIS IS NOTHING BUT GOOD OLD WILDCATTING AT IT'S BEST.

Of courss...this presupposes someone other than some strange experimenter would want to do it anyway...

Luck

I just got two boxes of .450 marlin brass from midway, I think they still have some.

Thanks...I have some coming from Graf & Son...they're prices are usually slightly lower than the rest for the brass and they have a flat $4.95 rate for S&H.

Hornady made a run...EVERYONE has 450 M brass now...for a little while anyway.

My little exercise way just to feed my need for knowledge.

Luck

I just got an additional 200 pieces of 450M brass from Graf & Son.


This brings me to well over 1K pieces of 450M brass.


I figure I can stop now.

oh... btw

since this is a 450M thread...

and just to beat a dead horse...

From Hornady

45-70

45-70 Government 325 gr FTX® LEVERevolution
Test Barrel (24")
Muzzle: 2050(fps) /3032 (ft-lbs)

http://www.hornady.com/store/4...-FTX-LEVERevolution/

VS

450 Marlin

450 Marlin 325 gr FTX® LEVERevolution®
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
Muzzle: 2225(fps) /3572 (ft-lbs)

http://www.hornady.com/store/4...-FTX-LEVERevolution/

Stocking up for the lean times I see.

I don't think the REAL 450M folks would ever acknowledge my tome as a "450 Marlin thread"...those folks and the 444M crowd are just as elitist as any BMW/HARLEY rider I ever run across... ... what I do puts me in the Banta poo pile. Those of us who hear a different drum get diss'ed by EVERYONE...hahahahah...ainnothang, mate.

Well....I never believe the ads anyway...just what my chrono tells me and that's only an approximation also.

I now have a 450 M BLR, a SMLE 458 American using case lengths from 2" to 2.5"(458 WM) that also shoots 45-70, 45-90 AND 45-100's and a 45-70 Marlin 1895 barrel due on Monday AND a 45-120 NEF BC I can shoot from 2" to 3.25" brass in...so I think I have the range almost covered.

I was thinking of rechambering the 1895 barrel to 450 Alaskan or reboring/rechambering to 50 Alaskan, but because of the pressure AND COAL limits on the square threaded Marlin I would actually loose some velocity in the 45 cal unless I used 525-550 gr bullets... ~1550fs...but still plenty enough for most sage rats.

Trying to make a penny with the Marlin is TOUGH work.!!!

Now if I knew enough about the Browning BLR and had a long action 300 Win I think I could turn it into a real nice 458 WM...I think that has been done already or at least thought of.

At least a dead horse doesn't get upset when youy kick it and just doesn't pay it no mind. Hahahahaha

Luck

FWIW

Gunshow this weekend and I found ONE box of 450 M Hornady and ONE box of Horn 265 JHP's 0.430"...and only 100 - 0.459", 500 gr RN hard cast bullets...plus a whole lot of overpriced "stuff", no bargans, 3 very high priced Win 71 348 Win's and lots of people doing spray-on coatings...but worth the 10 bucks entrance fee.

I measured the belt to base on the 458 WM I used in the test above at 0.211" and the new Hornady brass a 0.242"...MUCH DIFFERENT numbers that several online references and what I was using intially without actually measuring a Marlin case. This shows all that there isn't ANY substitute for actual, hands on, empirical evidence.

O.031" difference is considerably outside headspace limits but now I can see why a few people use "standard" belted mag cases without a major wreck. 0.031" is half what the calculated/referenced numbers shown of closer to 0.060" and why they have gotten away with doing it.

I still don't recommend using other than factory 450M brass in the 450 M chamber but done right by an advanced reloader, knowing HOW to do it safely, for myself only...I'm not scared.

In any event...not much interest showing so it's time to do some testing.

Luck.