I was thinking of sizing, trimming then annealing some fired cases and see if this would help with extraction. For.the most part I've still been using unworked trimmed virgin brass.
Looked at 50 B&M load data (a very interesting cartridge) almost exclusively imr4198. The B&M 50 uses rum cases keeping the slight taper but also headspaces off the mouth assisted by exclusively chambering in cfr actions. Might turn me to a mauser guy yet.
Guess I'll be off to town tomorrow after a couple pounds of 4198.
More on 50 B&M
http://m.b-mriflesandcartridges.com/50-B-M.html
[QUOTE=scope eye;271337]the most I have been able to fit is 90gr of H4895.[/QUOTE]
Struck out on any 4198 or rl7 but I did find some accurate 5744 never messed with it before kinda spendy.
I started at 50grs
Sierra 400gr JSP 50gr 5744 @1868
Fairly smooth extraction
350gr.Hdy XTP 50gr @1882
Fairly smooth.extraction.
That was the good. Went to 52.5 and was stiff extraction already 400gr@1908 350gr@1892 (case was beat up explains slight loss of.energy went.into blowing case.wall out)
I went to 55 and 60grs extraction went into mallet mode.
I got to 2007 and 2224fps easily but.the.extraction.renders.the load unusable.
Not that 1850-1900fps with a 350-400gr projectile.is anything.less.then.awesome. we don't.really get anywhere near 458 Lott velocity. Let alone 2500fps. Yes you can load and shoot 2500fps loads. As long.as you have extended bolt handle and a.mallet for extraction.
Will work up some usable loads next but they will be.more like a 45-70 then 458 Lott.
From my experience.I would say the short action version will probably have less.extraction issues and easily reach the same.if not even.greater velocity.
Think I'll try sabots. Might pick up a couple hundred fps that way.
Just had another brain fart. I have been using mag primers. A br-2 with the 5744 might work a treat.
Haven't been able to try em yet but I got some 250gr 45's in 50 cal sabots. We will get ScopeEye velocity one way or another and smooth extraction!!
Ok so didn't chrono it but did load, fire and.extract over 52.5gr 5744. Was nice to see some progress forward. I was beginning to get disallusioned with the 2000fps barrier.
I have to admit, watching your tenacity is very entertaining.LOL
Dean
RUMs are like woman in Stiletto heals, you know they are going to put you in the poor house, but that has never stopped anyone from pursuing them.
Glad to be of service Dean! This may be the way to go. We'll see soon. I'm gonna polish the chamber a little just enough to make sure tool marks aren't contributing. Though it looks very good. Accuracy over 2250 is phenomenal with the 400's. But if the sabots.can.get me there I'll settle for that. It's really weird.watching the sabot flying out of a freaking rifle!
250gr-sabot over 52.5 of 5477 4 shot avg @2204 easy extraction a fun little experiment.
100 yards es over 100 obviously.
I polished the chamber slightly tonight. Shot one round just for giggles 350xtp over 53.7grs of 5477 extraction wasn't hard but won't get to shoot more tests until tomorrow or? Didn't chrono it but I'm sure it was about 2050 ish. The speeds coming and extraction seems to gradually be coming around. Have a few sabots left but they are a last resort. Still a ways from my goal of 2350 with 500gr bullets. But I may have to settle for whatever I get.
Seriously hope to match the 50B&M but... we'll see.
Seems that polishing the chamber and my f/l die made some improvement. Also brass is.getting work hardened in a good way.
Am up to 56gr 5477 with the 350xtp and buttery smooth extraction. Previously my note from 55gr was "Get a freaking mallet!" So whatever it.is seems to be worthwhile. Will run the left overs over the chrono and take it up another couple. 60gr was just over 2200 and thats starting to look doable.
Polishing the chamber seems to have helped for you using those heavy loads?
I normally finish with 400 grit in the chambers....you think a finer polished chamber would be more beneficial for that big bore then?
If so, I'll start to polish the chambers for those big bores instead of the 400 grit I normally use and see how that does for the over all performance for all involved......I've haven't had any troubles form my personal barrel with the 400 grit but I also want to make sure NO ONE has any trouble out of the big bore.......PERSONALLY, I'm not a big fan of a finely polished chamber though. But I don't load mine up as powerful as you do either on a regular basis. (Call me a WIMP I guess!)
But if your getting better performance with heavy loads that way.....then that will be the way I will work those from now on.
BTW....if anyone else is having this type of trouble with your 50 HPDT.....contact me and I will polish the chamber and pay the shipping both ways for you.
Hi Jim. I believe it helped. Though as I mentioned previously it looked very good to start with. And I was a bit on the hot side to start. Deans posts had me a little over excited. Who wouldn't want to launch a 500gr missle at 308 velocities? I'm taking a much more sane approach and working up slowly.
Consider the barrel fully proof tested though!
I am confident the barrel is going to match the 50 B&M at least with 275-350gr bullets. I'm going hold off on the heaviest bullets until I've some solid loads for the 350's.
I'm also polishing the cases with steel wool which may have as much impact on ejecting as polishing the chamber.
Again thank you for giving us this unique chambering to use.
Only problem I see is theres no Praire Dogs up here. Though there seems to be possums all over. Dang hitchhikers!
Ok so as soon as I setup the chrono it starts raining. Won't complain its long overdue! But I got off 10 test rounds and managed to get six readings that looked accurate. Here we go!
All rounds were Hornady 350gr XTP's over accurate 5744.
54.5@1944
56@1996 & 2067
58@2140 & 2153
60@2153
All rounds ejected normally except the 10th which was the 2nd load of 60gr the shots.were basically done quickly though single loaded.
Weather what it.was I intend to load from 58-60 in .5 increments to see what's an optimal charge. Since todays results may not be accurate. But if they are somewhere near 58 will be the best I can do with this powder. Which looks good for 2150fps average. 60 is showing high pressures more due to the lack of increase in fps and felt recoil then on the cases and primers.
Good Lord Almighty! That round is HUGE!
Clearly my numbers last post were skewed by the rain. The best consistency to date with 350gr Xtp's and accurate 5744 were at 60.5 grains.
Hight 2164
Low. 2134
Avg 2148
ES. 30
SD. 10
This is pretty hot. Primers are flat but ejections consistently smooth. I am calling this max load for this powder and bullet. Which I'm out of until I can pick up some more. I am going to work on the.400's should be.very close to the same charge. My son stopped and I had him shoot 7 rounds of 400gr over 59 gr 5744 they ran just about 2025fps. Pretty sure he likes the round even said its pretty BA! He was suprised how managable the recoil was. No doubt the recoil pad gets some credit there.
I should add that I took the 350gr XTP up to 61gr 5744 shot 10 rounds with fps up to 2200 with 1 as low as 1990 primers were not only flat but deeply cratered. 1 actually showed signs of cracking micro sized and very faint signs of.gases.escaping. Some looked.fine and.I suspect the.crimp may be the.differences. its difficult to control.
Am going to go ahead with tac again. Will see if the 83gr loads will extract now. I don't see 5744 giving me the velocities I'm after with the heavier bullets. Tac was clearly there without a hitch.
One thing I can say these hornady cases are awesome. Some of the abuse I put them through to date its just amazing. Pretty much using the same 10 pcs over and over. Which means they have at least 8 loadings.
geezuz! how big are the bears up there?
Jeff518
True bears.get pretty big here. Not a lot of competition and under hunted. No idea what average is but commonly they go 325. Really its the gophers ya need this bad boy for. You have to be close and you don't get time for a followup shot. Lord help you if one gets through your defenses and the lil fart runz up your pants to chew off yer nutz!
Got out to shoot this a little today with the 400gr bullets over 82.5 grains of Ramshot tac@2025 avg. This is a pretty stout load. Extracts well but I did have one primer get loose this was on its 9th load so wasn't exactly a huge suprise. This rifle shoots really nice I had better groups with the 50 today then from my newish 7mm rm but in its defense the 7 just shot its 100th rnd on the factory barrel which could really use some lapping as the rifling is so crisp n sharp it copper fouls quickly.
Got side tracked with the big 7's my neighbor brought his 72 700 over too. He was trying to get a consistent zero with Remington cor lokts 175gr factory loads. We ran a 10 shot string over the chrono and got an ES of 110 which probably explains the 3-4" groups. Just before it got dark I had him shoot 5 168gr Berger Hunting vld's I had jumped over when working up my load and you could easily cover the group with a quarter. I'm not sure it proved anything other then my loading is coming along nicely.
We estimate his rifle to be well over 2500 rounds probably closer to 3000 so really its holding its own very well.
For the 500/375 I'm going to order some swift A-frames 325gr bullets next. These are rated for "3000 fps and beyond". If they shoot well based on cost and the likely potential of reaching 2250 safely with enough down range energy to be effective out to 300yards it seems like a no brainer. We'll see if it pans out! So as of today round count for my 500/375 is 90 and each time I shoot it all I can say is "Gawd I love this gun!".
Finally scored a couple pounds of rl7 as soon as the rainy overcast weather stops I'll give some of the 50 B&M loads a try. Somewhere around 76grs should work. Still looking for 4198.
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