I just picked up a new Remington 700 Sendero in .300 Remington Ultra Mag and was wondering what loads ya'll have found to be sucesfull?

I picked up a pound of H-1000 and 100 cases. I have only smaller .308 bullets on hand (155 Palma SMK's, and 165 Hornady BTSP's) I was wondering if anyone had something using these componets?

Also, what would be the ieal weight of bullet for a .300 Ultra Mag? I was thinking it would be in the area of 180-200gr but was not sure. Also please suggest any powders that you have tried and worked!

I can't wait to shoot this cannon. It will be my first real hot-rod and I am pumped!

I just started reloading this caliber for a friend so I'll be watching the answers. Unless you have a muzzle break or love getting "beat up" you'll probably be glad you have those lighter bullets to practice with. You should be able to go to Hodgdon.com and get some good info on your powder. I would say the ideal bullet will be a 180 or 200 grain premium. Tsx's, accubonds, swift a-frames, partitions etc.

Well I am not too worried about the recoil. I shoot religiously with another member here on the board and don't have problems with his unbreaked 8mm-378, 338-378, 405 Win.....

I know this thing can be a kicker, but I figure if I can get the weight around 12-13lbs I will be all right. I may invest in a limbsaver, but that will come after a new trigger.

Thanks for the advice!

Remington Brass
Remington 9 1/2 primer
180 grain Swift A Frame Bullet
96 grain RL-25
MV 3350
Excellant three shot groups @ 100 yards

Good-Luck

Steve

The 300 RUM is a lot more interesting than it appears on its face, as it has the same expansion ratio as the 50 BMG. With bullets 180 grs and up H870 and AA8700 are simply great and will top slow extruded powders by 100 fps at lower pressures in a 26 inch bbl.accuracy can be superbe.

Waffen-good luck to you, things should work out well for ya.

Now about the recoil I would not worry one bit, usually the fellas that talk about this stuff don't have much for big gun experience. Sounds like you do so no worries.

Mark D

IME they do not have that much for recoil, just a good sharp quick bump is all

Oh and one other thing a couple of bullets I would work with right off would be the 168 and the 180 TX.

I would have to think that R22 or R25 would work just fine with these.

I've got a friend that uses R25 and 200 Accu's and just loves it.

Mark D

My own 300ultramags like the 180gr tsx and r-25.The 180gr tsx is plenty of bullet for any game in north america.

Well, I just learned my first thing about loading for the .300RUM. My little Frankfort Arsonal tumbler does not like more than 25 cases at once!

Can you say loud!

88gr H1000 with 200gr SMK
87-88gr Retumbo with 216gr clinch river

My 300 ultra likes the 165 grain barnes triple shock, 99 grains of magpro, fed 215 primers , and remmy brass. Good for 3500 fps and the bc of that bullet is a click above .500. Run that on your ballistics program, it will make you smile.

94.0 grs. of Reloader 25 pushing a 180 gr. Swift Scirocco is my tack driver.

I have a rem 700 Police .300 RUM with MK 4 6.5-20x50 leupold with mil dot reticle in badger rings and 20moa base along with a canjar trigger and after having a play with the lighter 150 gr Nos BT's I havenow moved up to the 200 gr Noss AB's (there BC is .588)

Anyway my load with the 150 gr Nost BT's was

104 gr of AR2225/Retumbo Rem case Fed 215M OAL of 3.681" or as long as possible and be able to use the magazine. Groups where in the .5" at 110 yards. One load using 106gr shot in the .2"'s but it was a tad to hot.

I have worked up a load of 92gr of AR2225/Retumbo behind the 200 gr Nos AB's that shows promise.

I have found that many loads that seem mild with the RUM leave ejector marks in the Brass..............I would like to have different brass than Rem cases.

The Sendenero's and PSS's are very accurate guns.

To really take advantage of the 300 ultra, i shoot the heavier bullets. Right now I'm shooting the 220 matchking or the 210 berger. Depending on what youre hunting I would step up to the 180 or 200 accubond.

Al what are your laods ??

Hey PC, the 220mk is shooting the best with 89.3 grains of Retumbo. It shoots about 1" at 320 yards, 4.5" at 700. I have about the same accuracy with the berger and 91.5 grains of retumbo. I keep the matchking .005 off the lands and the berger jammed .015 into the lands. I have a bunch of 200 accubonds but I didn't do to much testing with them. I am away from home and I can't recall the exact load with the accubond but I believe it was somewhere around 93 grains retumbo. They showed a lot of promise but I wanted the higher bc of the match bullets and the 220 matchking will devastate any deer in my area. I would bring the accubonds out if I was going after an elk or something larger than the small whitetails in my area.
I have had the same experience with the ejector marks. I bought some federal brass after many people raved about it but the primer pockets are VERY loose after one firing, whereas the remington was giving me at least 4 firings. I have fired some of the federal twice but havent tried for 3 firings, i don't think the pockets will be tight enough.

Waffen,I just ordered a 700BDL in 300RUM. I will get it in a month.Got that because I can convert to 375 RUM if I wish.I look forward to using these posts in finding a load.BTW,I have a Sendero in stainless.I regret getting it in stainless.My gunsmith does not like stainless actions of that type.I also find the stock shape to be weird for a hunting rifle.

92 gr RL25, 200gr accubond, fed 215M, Rem brass= 3150 fps ave chrono'ed and awesome accuracy. Most 180's shoot good with RL25 too; in the 94 to 96 gr range. With any stated load, work up from well below to be safe as each rifle is different.

I've reloaded for 4 different 300 RUM's. The first one liked 180gr Partitions and RL-22 but the other 3 performed the best with 200gr Accubonds and Retumbo. IMHO the lighter 150-165gr bullets are a waste of time and barrel throat in this caliber.
I would strongly reccommend that you try 200gr Accubonds and Retumbo for starters. There have been other posters who have gotten similar 1/4 MOA groups as I have with this combo...............DJ

Al,

I had one very accurate load at 83 gr of retumbo behind the 200 gr AB but that load was not even at .300 win mag max charges............................I have never experienced a gun/caliber to give ejector marks as easily as this

PC, that is a stiff ejector spring sign. If you are not running 300RUM speeds, you need more powder. I don't know what action you have but The rem700 especially IME has a stiff ejector spring and with good tight fitting fireformed cases, that spring is under stress before the round is ignited. I have my springs ligthened a tad to make them sit more squarely in the chamber and so that the spring does not force the case mouth/neck against the inside lug rail and dent it as it is being ejected. I had this done in my win70 action as well

Just C I have a rem 700 police .300 RUM.............the mild load above does not produce the ejector marks but the 92 gr loading does (Retumbo/AR2225) & 200 gr accubond. I feel the 92 gr load should not be over pressure considering that really it's only 8 gr more AR2225/Retumbo than the .300 win mags mx charge for the sma ebullet weight, the .300 RUM should be able to handle 8gr more powder than the .300 winnie withou pressure. So maybe you are right ??

Funnily enough a few reloaders of Rem 700 .300 RUMs have had ejector marks issues with what wouldn't seem like high pressure loads.

Data in Oz is of no help............adi make Hodgons retumbo and the 200 gr data for hodgon and adi lists 86 gr as the max charge for retumbo and AR2225 (Rtumbo is what ar2225 is packaged as in the states)however the bullet used is the Barnes X 200 gr bullet which has a longer bearing area and most likely less give than a regular lead jacketed bullet.

Al I would like to try the 220 smk's at some point what is there bc ??

also will the standard Rem barrel stabilise the 240 gr sierra Match kings ??

Hey PC, the listed BC is .629. I don't have a chronograph but based on others load data when I guess on my velocity and input this bc in a ballistics program it matches up perfectly. I could be off with my velocity though.
I have a 1 in 10 twist, 28" lilja. Your barrel has a 10 twist also. I have not tried the 240's, I would like to try them but I don't think sierra is making them right now for some reason. I could be wrong about that though. If you happened to have some of them, I would think they would stabilize, I have overheard several people saying they have shot them out of the 700 police with success, same gun you shoot.

thanks al.........I have not got a pack of the 240 gr smk's but I think they would be worth trying, I am quite fond of the .300 RUM round it is a lot of fun.

I shoot both a Rem. 700 BDL and a Sendaro in the 300 ultra mag. Worked loads with a few different powders but found IMR 7828 with 180 gr. Nosler Partition to be the most consistant in both. Although the Sendaro will shoot about .5 tighter at 100 yards it made it real simple to use the same load in both rifles. Have taken numerous Elk, Deer and Bear with that load as well as a Leopard, Zebra, Warthog, Kudu and Impala.
Scott

I have been using the following with excellent accuracy:

200 AB over 89.0 Re25, Rem or Fed brass, with the Fed showing no ejector marks.

180 Scirocco over Retumbo, don't remember the charge offhand.

WLRM primers in both cases. Thinking of trying the WC872 powder to see what happens.

While in CO this past OCT, the 200 AB/Fed brass combo one holed 3 shots 2 times in a row at 122 lasered yards.

Rem BDL 700, 28" Shilen select match grade bbl, #4 contour.

Although the Shilen bbls were the first 2 custom bbls I ever ordered, I heard later that there were better bbls out there, like Lilja, Broughton, Krieger, etc. now I have a few of the latter, but those 2 Shilen bbls I own were the first rifles to produce repeatable 1 hole groups. Sorry, got off track.