Picked up a 300RUM Sendero and need to start some loads. I have Remington cases and have received the following dies RCBS Neck Sizer Redding Body Die RCBS Seater Lee Factory Crimp I have taken the expander ball out of the neck sizer and it sizes the outside to .332" and have outside neck turned the brass down to .0135" thick which should give a grip of .003". So now to stretch the brass I would like to try 180 gr TSX 200 gr Accubond I can load the TSX to within .060" of the lands and still fit the magazine but the 200 gr Accubond is going to be .110" out. Seems to me the appropriate powder would be 180 gr bullets - RL22 200 gr bullets - RL25 both of which I have plenty of. I also have plenty of H1000, IMR7828SSC, H4831, IMR4350, RL19 and IMR4831, all of which are possibilities. My Nosler #5 shows 87 gr RL22 as the max load so a possibility would be 180 gr TSX - 85 gr RL22 180 gr TSX - 86 gr RL22 180 gr TSX - 87 gr RL22 But for the 200 gr I have no listing for RL25. If I wanted to guess I would say 200 gr AB - 85 gr RL25 200 gr AB - 86 gr RL25 200 gr AB - 87 gr RL25 Should I use the IMR7828SSC instead with the 200 gr AB? This is just stretching the first 25 cases but I would like to start at a meaningful powder charge but still be well within safety ranges. What I'm looking for is someone who has gone through the development stages as well. Good to go?

I recently got a 300 RUM Sendero so I'll be interested in your progress. My plan was to start out with Retumbo and H1000. My bullet choices will be... 180 E-Tips 200 AB's 210 Berger and/or JLK VLD's 177 GS HV's and possibly some wildcats. My choice of dies will be Redding neck sizer and competition seater and might get some custum dies later. Keep us posted on your progress, MR

my pet load for the 300 rum is the 180grAB, 95grs H1000.....3250 fps or there about....minimum spreads, good groups....the AB performed well on a buck and bull last yr that my son harvested.....AJ

My factory sendero liked 87 grains of rl-25 with the 208 amax 84 or 85 grains to start out should be very safe my other load with the broughton barell is 88 grains of h-1000 210 berger it loves this one 3 shot group @ 100yrds you can cover it with a dime I NEVER RAN THEM THROUGH A CHRONY MY OAL WAS 3.060 ON BOTH LOADS

I have seen this load from 88-89.5 posted several times by different people in other threads and forums. With that many people using it it mast be ok.

Woods If you search for the RUM loads here and othe places you will hit some interesting info. Retumbo seem to be the go to powder. However, seems that guys are finding the load to be from 91 to 96 gr Retumbo and some are pressuring out at 91-92 gr so be careful. MV is widely varying but topping out at 3250, and not related to the high end loads. that is with the 200 gr Accubond. Some are having good luck with RL25 and MRP2. Have not seen any with RL22 Mag primers are normally used. either the Fed 215. Rem or wolf 200 gr Accubond is great choice to start. BH

I've found 96.0 gr. H-1000, fed. 215, with berger 168 vld to be the best in my pac-nor bbl. 5/8" @ 300 yds. 3360 fps. Max in my rifle but shoots very well.

Rifle started as 700 sps, then (after burning bbl @ 272 rounds!) installed pac-nor bbl,with vais type brake, trued action, minor trigger work on stock rem trigger, and accurate innovations stock, (and much, much range work) with a few conversations with berger i settled on that load. Works for coyotes/antelope/deer/elk.

I am shooting 180 accubonds in front of 90 gr of rl22, mv 3250 accuracy, one hole! My friend is doing the same with 180 sciracos with 90.5 of rl22. I tried H-1000 and it shot good, just not as good as the rl 22. My next tests will be with retumbo.

Nobody had any 180 grain barns for me to try out so I went with the 168ttsx and pushed it with 97 grains of h1000 and fed 215 primers and got less than .5 inch groups at 100 yds 5 shot group, 3330fps and a coal of 3.760in I have shot these out to 700 yds and had good luck with them keeping about .75MOA at that distance but it was a little breezy and I didnt have a very good rest so I need to do it again... Barns have a very low BC and dont work to well at longer ranges max effective range with the bullet still performing is 700yds in my rifle.. If you can get the swift sciroccos to shoot out of your rifle I would go with the 180's for that I had great luck with accuracy and theh have a higher BC and I took a lot of game last year and was very impressed with how well they worked I killed a 150 lb caribou and up to a 1500 lb moose with them and nothing went farther than 20yds but I cant get them to group out of my RUM (damn)

I've been fooling around with the 208 A-Max which I intend to use on whitetails. I believe the BC is .648 and should be good for the looooong shots. Yesterday I loaded up 99.0gr of Hodgdon 869 with a 215M primer. Shot a .55" (3 shot) group @ 200yds. Pressure seemed modest as bullet cruised along at 3,035 ft/sec. Not exactly neck breaking velocity but incredibly accurate. I'll load up some more and see how they shoot at 300yds. I'm also interested to see how an increase in charge weight affects velocity and accuracy. Currently shooting a 27" Broughton 5C.

I've been using IMR-7828 with 180gr bullets in my 300RUM took one bull with that load. I just picked up acouple box 190gr Hornady's going to be trying Retumbo.