I have loaded 180 gr. TSX in my Sendero 300 RUM. It took quite a few trys to get the C.O.L. right but it was worth it. At 100 yrds., 3 shot groups, it shot .14" center to center. I almost got discouraged with the bullet until I talked w/ the tech. support at Barnes. They were very helpful and encouraged me to continue on. After about 30 - 35 loads, I hit jackpot. I shot a 180lbs. boar last week at about 100 - 120 yrds. The bullet retained 179 gr. of 180 gr. The hog accually did a complete flip at impact. I shot the hog in the head which had a .30" entrance hole and about a 2" exit hole. I shot through 7 gal. of water at 100 yrds to retrieve the bullet. The bullet was almost 3 times the size in diameter.


My COL is 3.640".

From this guy I know... His name is Jay and he is a CPA.... He can do numbers but not letters.

I seem to be seeing a lot of used 300 RUM,s in the used rifle racks of local gun dealers. After reading this thread, I am beginning to see why.

Thanks, Clint

The main reasons that a lot of 300ultramags are appearing on used rifle racks are:

1)having a long range cartridge does not make a person a long range shooter.Most
peoples shooting skills are not good enough to take advantage of the ultramags
super flat trajectory.

2)The ultramags recoil is not usuallya problem for experienced shooters that shoot
often but it is often a problem for people that don't shoot a lot.

3)The large capacity magnums like the ultramag can be a little more fussy as to the
loads that they prefer.

The primary reason that I sold my Browning Stainless Stalker in 300RUM, was because I figured by time I worked up a load, the bore would be shot out. I have broken in and worked up loads for any number of cartridge/rifle combinations in over 45 years of hunting, reloading and target shooting, and I have never encountered such a finicky piece as that one was. Sure, the concept was excellent, having a non-belted long magnum sounded like a great idea for working up the optimum load for long range game taking. Evidently, from what I have read here, several things come into play, to include:OAL, type of propellant being JUST right, primer and bullet choice, topped off by quick and heavy bore groove clogging. Certainly one has to be aware of these factors in reloading for any high powered cartridge, but with the 300RUM, each factor seemed to me to be excessively critical. I admit, I gave up. I bought a Winchester Ultimate Shadow in 7mmWSM and had a tack driving elk rifle, ready to go, after testing with less then 40 rounds! My experience is no reason for anyone to make any conclusion, regarding the 300RUM, as I only dealt with one rifle in this caliber. However, once burnt........
Steve Ashe

Steven, tell me no. You gave up? And didn't give me chance to buy. I understand. I have burn out one barrel already myself.

Yeah, Bigcountry, I have not been stymied by new calibers in the past, but that 300RUM was too much of a puzzle. After four different propellents, five different bullets and countless load data, I figured that I had been whipped and sent that Browning/300RUM rig down the road.
The Winchester Ultimate Shadow in 7mmWSM is working out really well and if what I hear on this list is true, I should not need more then a 140gr premium bullet in 7mm anyway. The Winchester was shooting well, but I had a trigger job done anyway, as the trigger was a tad stiff and did creep a bit. Will report after again range testing.
Thanks for the help that you did render. Steven

Well, at least you didn't take to the extreames I did, and have a 500 dollar rebarrel job. It worked wonders.

Like I tell everyone, this is a finicky cartridge. Don't expect it to be like a 308Win with 15fps velocity spreads. Get used to to those 70fps spreads. But when you find your combo, it can be very satisfying.

Anybody have suggestions for a 200 gr. bullet? Particularly the Partition or Barnes Triple-X? Or is the difference between 180 gr. and 200 gr. for elk negligible?

bigcountry did say: I do not know, on average, how many rounds a 300RUM can swallow before going off it's feed and throwing wide patterns. I have heard that this will occur in a 300RUM between 800 and 1200 rounds. Someone told me earlier that if I expected to get 3000 rounds out of a 300RUM, then maybe the 300RUM was not for me. I now acknowledge, that the gent was correct. I want to fire my deer elk rifle, at the range, throughout the year. It would not be unusal for me to put 1000 rounds through my rifle, between seasons. A finicky cartridge is simply not worth the stretch and it has nothing to do with the cost of rebarreling. Rebarreling only means that the exercise begins all over again. The only thing that may have helped, would have been an OAL gauge, but when I got into the 300RUM, I just didn't realize how finicky the thing was.
The 7mmWSM, although new to me, is very similiar to loading for a 30-06. Load up five or six hot loads and one or two of them will print inside 1" @ 100yds, or better. I have to put up with PITA situations at my clock shop, but I do not have to put up with same at the range.