Finally got my 300 RUM sendero to shoot

[dmproske]

Well it took a while but I think I am close. This is a stock Sendero cept for a break and trigger work. I am trying to stay with the 200 grain Accubonds. All loads Remington brass and Federal 215 primers.


Retumbo did not shoot worth a crap regardless of seating depth. Tried 93,94,95 grains. 93 shot 1.5" and the groups went up from there at 100 yards to over 2.2". She just does not digest Retumbo

I was getting worried and per my other threads was thinking it was runout causing my grief so I am waiting for my neck turning tools and die bushings to arrive. So many fellers here said their senderos loved Retumbo. Thought mine had to as well and was thinking I got a bad barrel.

H1000 did just a little bit better. Tried 88,89,91,92 grains. 89 shot 1.00", the rest was 1.5-1.7" 3.680 seating depth.

Reloader 25 shows promise. Tried 89,90,91 grains per what other posters quoted. 89 grains did .55" right off the bat. 90 did .70 and 91 was at 1.00 but I pulled the last one when the shooter next to me shot his magnum and made me jerk. 3.680 seating depth.

I will continue with the Reloader 25. Hopefully when I turn my necks and get runout down things will improve. These loads varied two thousanths-six thousandths runout.

No pressure signs at all with any loads.

Can anyone with quickload quote approx velocity with 89 grains RL 25, 26" barrel, 200 grain AB?

 

[mrultramag]

I don't have quickload but I run the 200 AB, 92 gr RL25, Fed 215M, rem case, oal 3.650 and at 15 ft it chronographs an average of 3150 from a stock rem 700 BDL 26 in bbl, 300 ultra mag. Its my go to load.

 

[clhman]

I had a hard time with retumbo also with my Sendero 300 RUM until I tried it with 180 Nosler Partitions. I use 100.5gr and seat to 3.680. Velocity is 3415fps and accuracy is .75MOA. I don't know what you are looking to shoot, but the ballistics can't hardly be touched on that load.

 

[Eaglet]

I had a hard time with retumbo also with my Sendero 300 RUM until I tried it with 180 Nosler Partitions. I use 100.5gr and seat to 3.680. Velocity is 3415fps and accuracy is .75MOA. I don't know what you are looking to shoot, but the ballistics can't hardly be touched on that load.

clhman, unless you are using a custom 30+ inches barrel, I would back your load off. 180 gr. Accubond with Retumbo will give you a max at about 3350 ft/sec and you've got to be very careful shooting in extreme temperatures. Just a friendly advice. 3415 is way to high unless your chronograph is not reading properly.

Accubond 180 and retumbo hot load ---- 3350 ft/sec
Accubond 200 and Retumbo hot load---- 3215 ft/sec
Beger 210 gr. w/Retumbo hot load ------ 3150 ft/sec

These loads should be approached slowly and carefully.

 

[Eaglet]

Can anyone with quickload quote approx velocity with 89 grains RL 25, 26" barrel, 200 grain AB?

dmproske, the Nosler #6 reloading manual says that 89.5 gr. of RL25 would produce 3125 ft/sec.
One of my RUMS chronographed right at 3100 with 89.0 grains.

 

[dmproske]

Thank you. Thats what I was looking for.

dmproske, the Nosler #6 reloading manual says that 89.5 gr. of RL25 would produce 3125 ft/sec.
One of my RUMS chronographed right at 3100 with 89.0 grains.

 

[WildcatB]

You might be able to tighten things up by trying .5 grain increments of powder. Although .55" would be good enough for me.

 

[clhman]

clhman, unless you are using a custom 30+ inches barrel, I would back your load off. 180 gr. Accubond with Retumbo will give you a max at about 3350 ft/sec and you've got to be very careful shooting in extreme temperatures. Just a friendly advice. 3415 is way to high unless your chronograph is not reading properly.

Accubond 180 and retumbo hot load ---- 3350 ft/sec
Accubond 200 and Retumbo hot load---- 3215 ft/sec
Beger 210 gr. w/Retumbo hot load ------ 3150 ft/sec

These loads should be approached slowly and carefully.

Forgot to mention, I'm in Alaska. Loads were okay at 20-25 degrees. Barrel is stock 26" with a Wild West Guns break. I took a moose with that load in September, temp was about 45 degrees, no signs of pressure. I am a newer reloader. What do you think I should do? Am I hurting my gun? Today it is 9 degrees. I thought about shooting it again to check the velocity.

By the way, I get 3550fps out of 165 Sciroccos with Reloader 22. (Same velocity with Reloader 25, just not good accuracy.)

 

[jwp475]

clhman, unless you are using a custom 30+ inches barrel, I would back your load off. 180 gr. Accubond with Retumbo will give you a max at about 3350 ft/sec and you've got to be very careful shooting in extreme temperatures. Just a friendly advice. 3415 is way to high unless your chronograph is not reading properly.

Accubond 180 and retumbo hot load ---- 3350 ft/sec
Accubond 200 and Retumbo hot load---- 3215 ft/sec
Beger 210 gr. w/Retumbo hot load ------ 3150 ft/sec

These loads should be approached slowly and carefully.

As usually Eaglet is spot on

 

[Eaglet]

What do you think I should do? Am I hurting my gun? Today it is 9 degrees.

clhman, I'm more concerned about you hurting your self; a gun can be replaced but not so with your person. Chamber pressures are extremely high with your load and I would definitely lower the powder charge. According to Nosler's latest reloading manual, 99.0 gr. of Retumbo would reach maximum pressures at about 3343 ft/sec. Some rifles would reach that with less powder and some with more, there's where a good chronograph comes pretty handy.

 

[dmproske]

When I originally posted the information on the groups I was measuring edge to edge. I was unaware people typically post center to center numbers.

The good group I got with 89grains of RL 25 under a 200 accubond was .55 edge to edge. Corrected number is .242 center to center.

 

[johnnyk]

dmproske
Well now, going from .55" to .242" puts a much better view on your rifle, your reloading and your shooting ability, doesn't it? That's great accuracy. I would be happy with that from a 7mm to .243, but for a .308 cal rifle, that's exceptional.
I had a .300WM Sendero years ago that gave me a fit to start with. It didn't seem to prefer anything I shot in it and groups ran right at an inch. Then after about 75-100 rds through it, it just kinda mellowed out, settled down and started shooting good to great. As I look back, it was probably the barrel getting broke in good. Too young and inexperienced to know what was going on. JohnnyK.

 

[dogdinger]

"This is a stock Sendero cept for a break and trigger work."

just my 2 cents worth......the accuracy you are getting is prob better than average with a stock sendero. i have one in 7RM and had a hard time getting it to shoot good groups. My suggestion would be to give it a good bedding job on the action and recoil lug. Mine would not shoot without a good bit of forearm tip pressure until i bedded the action and lug. now it shoots great with the barrel floated. AJ

 

[Michael Eichele]

I agree with eaglet. 3400+ is just too dang hot for a 180 in a 300 RUM. This is coming from a guy who has been using 2 different 300 RUMs over the last few years, top quality I might add. I have tested loads between 3375 and 3400 too but I wouldnt advise it. Hell I shot a 180 ACCUBOND at 3709 once. I needed MAJOR bolt repair after that. I am lucky thats ALL that went wrong. I have found that about 3300-3350 is about all any 26"-28" 300 RUM can realisticaly handle.

As far as RL25. It has been all around the best powder for both my 300's. Best being best velocity and accuracy. I had problems with extreeme spreads but annealed my brass and now I am in single digits on a good day and less than 20 on a bad day. Even the highly esteemed H1000 hasnt yielded that small of spreads for me. I too have not been able to get RETUMBO to group the 200 AB well and H1000 plain sucks in my rig with the 200's but does extreemly well with the 178 AMAX.