Ok here is my story and I'm sticking to it. I bought a 300RUM Sendero, before I even shot it I took it to the gunsmith and had some work done to it. I put a sightron S111 6-24x50. I went out and bought 10,000 Fed 215 primers, 200 rounds of Remington brass, 200-155gr berger bullets, 100-168gr berger bullets, 100-175gr berger bullets, 300-185gr berger bullets, 100-190gr berger bullets, 100-210gr berger bullets. For powder I bought 3lbs of Retumbo, 8lbs of Ramshot Magnum and 1lb of Hodgdon US 869. Then I also bought 100-208gr hornady Amax bullets. At first I was going to decide on the 185g bergers. Tried both the Retumbo & Ramshot Magnum powders. When I have been loading ammo I am taking two measurements, base of case to tip of bullet "3.600-3.620" and measuring from base to Ogive "2.944-2.950". My rifle has a 3.600 OAL and a 1-10 barrel twist. I used a hornady Overall length gauge. My magazine will accept a round as long as 3.678. The measurement I get to the lands is 3.822. I have went out twice and shot my gun, have only shot out to 400 yards, but more concentrated with 100 & 200 yards, my groups are very sporadic. I am finding out that I know very little. I am going to load a few rounds out to the max, but the last thing I want to do is make my gun a single shot. I had read early on that berger bullets worked best being seated at or on the lands. I had also heard that the 300RUM likes heavy bullets. Walt at berger said I should load a few rounds that are closer to the lands. It also may be that my gun does not like berger bullets. I am hoping to have a gun that will shoot out to 1000 yards.

So can anyone make heads or tails of all this???

This may not be what you want to hear. but this is my experience with the 300RUM.

I reload for two of them. One is mine and one is my best friends. One is a Remington BDL, and the other is a Remington LSS. both rifles shoot pretty well. They are fully capable of MOA accuracy, or slightly better.

These are hunting rifles so I did not do all the reloading tricks that I would do for a varmint rifle, but here is what we did.

First I seated the bullets are far as the magazine would allow without tip deformation in recoil.

We load the Sierra 200 grain bullet with RL-25. It did not take any time at all to develop a MOA load for the rifle.

That cartridge is truly awesome. Our two rifles like the heavies(200 grain bullet). But I will admit that we did not even try the lighter bullets. We wanted to shoot the 200 grain bullets. Good luck with your reloading. Tom.

90grs RL-22 168gr Berger vld hunting bullet seated 10thousants off the lands, Fed 215M. Shot it last weekend out to 300yds, one inch group. Let a friend who has never shot beyond 200yds and nothing bigger than a 308win. His group was just over 2". The action is bedded and the barrel floated.Rick.

Freebird have you had the trigger adjusted? The reason I ask is because I just bought a Remington sendero vssfII and the trigger pull was 7lbs 7oz.

I loaded some 165 nosler BT over a max charge of Retumbo with a 215 match primer and my gun would shoot a into 1 to 1.25 inch and I thought that was poor accuracy for a bull barrel gun. I am hoping things improve with 180 grain bullets.

How poor is yours shooting?

Dink

Many cartridges have a common combination that a miriad of shooter discover independently and the .300 RUM is one such cartridge.

A load consisting of 94 grains of Retumbo behind the 200gn Accubond will very commonly shoot into .5 MOA groups at 100 yards. I have loaded with 3 rifles in this chambering and it was relatively easy to find a .5 MOA load in each.

The common denominator in my case was bonded core bullets which I believe are the most accurate or among the most accurate bullets you can hand load. All 3 rifles loved Woodleighs even when I pushed the load faster than Geoff McDonald recommended.

JW

Yes I had the trigger work done, its at 3lbs pull. I know some of the shots I crackered. You would have to use a circle the size of a coffee can lid to cover my holes. In the past I had very good luck with Nosler accubond bullets in my wifes 300SAUM, 150gr accubonds shoot great out of her gun. I have bought a bunch of berger bullets thinking they would be great. Then went out and bought some 208gr Amax bullets, have not loaded any of those yet, had emailed hornady asking about some load data for the 208gr Amax bullets and they just told me to use the 220gr load data, I felt that was a lame reply. So I just have to settle on a bullet and powder and concentrate on those two factors and hope I can create a great load.

Freebird have you changed the scope? Did you make sure all the rings and bases are tight? If your shooting groups like that I would think the scope is bad. Also check the action screws and make sure they are tight and maybe make sure there not to long and putting pressure on the action.

Dink

Aussie,

Did you happen to chronograph that load?

3164 fps and 4447 FPE

Model 70 SS Classic.

JW

Thankyou, I have that same combo ready to go as soon as the weather improves.

Checked all the screws everything is tight. I see that most everyone states their groups at 100 yards, is that the norm??? I am going to zero my gun out at 200 yards and go from there. Today I loaded some ammo, played around with seating depths. I have a feeling I got this figured out now. So as soon as this Idaho weather cooperates I will get back out see if I got it solved.

My barrel is a 28" Benchmark 3 grove 1:12 barrel, the contour is a copy of the sendero, it has a 2" long muzzle break adding 2", for an overall length of 30". I shoot the Hornady 30 cal 208gr AMAX pushed to 3200 fps using US869. the groups are sub 0.5 moa.
I did go thru my brass and debur the primer flash holes, uniform the primer holes, trim to length, and turn the necks to a uniform thinkness.
I have not found that it is necessary to ream the inside of the necks yet do to brass flow.
My brother has a Rem M700 LSS in 300 RUM, he shoots RL-25 with a Nosler 180gr AB @ 3400 fps into sub 1 moa.
Sometimes with light bullets and low end powder charges, you will get irratic ignition and pressure, this will screw up your groups.
I recommend you switch to +180 gr loads and continue developing your loads.
FWIW, I used Hornady 150gr bullets to fireform my brass and break in my barrel. I did not pay a whole lot of attention to groups sizes with those loads, just the patches coming out the end of the barrel. I think I had 50 rds into a 2" group that day. I used old 4831, and 20 yr old primers, saving the new ones because they were hard to come by this time last year.
Good luck - take your time and make sure all of the screws are tight on your rifle. If you want to sell, my son is looking for one.

I had the XCR and it shot 2moa out of the box, I had it restocked with a Bell and Carlson and now it shoots sub MOA, I also noticed that it does not shoot as well clean and that I have a sweet spot of between 10-30 rounds where my accuracy is best. I load it with barnes TTSX 168, and 7828 ssc(super short cut). I have, and not sure if it was luck but shot a 3" group with it more than once but not more than twice, at 600 yards. I had it worked on at www.scorehi.com