Sendero 300RUM - 1st Groups

[Teknys]

180 BT and Retumbo, actually 6 shots after a bore clean and foul shot.

This group was with a full charge of Retumbo and 200gn AB, shots 1,2, & 3 went into the same hole and I pulled shot 4 and hung my head before looking down range at the target too see where I sent it.

I went out to break in the barrel and after 10 shots I tried some grouping at 100 yds. I think this barrel is off to a good start.

One of the four brass w/ the 200AB had a "crater" firing pin mark, no sticky bolts or any pressure signs other than the one crater. Is that something to worry about or should I back off a grain.

 

[Powerstroke]

Congrats ! Looks like you've found your load right out of the gate !

The RUMS are a wonderful cartridge....

 

[DrMike]

That load will work! Congratulations.

 

[nodak7mm]

Schweet. Great feeling outta the box like that. Go buy a couple of lottery tickets..

 

[6mm Remington]

That's pretty incredible for right out of the box with some first time loads!! Good job!

As far as the cratered primer with ONE of the primers, it could mean the pressure is up there a little, but there are other things that can make it appear that way. I don't know if you were using Federal, Winchester, or some other brand of primer. ONCE in a while just like anything, there can be some problems with any product. If you took these primers out of one little box of 100, and do not have any more boxes of that exact primer, by meaning a brick of them, try loading the same exact load and primer with four rounds again but from a different lot of the same primer. Possibly the primers were a little soft. WE had some 7mm REM mag factory ammo one time, and the Winchester brass we used was not annealed properly and was soft. The load was a safe proven load, but with a new freshly loaded factory case, the primer pockets would expand. Sometimes the primers would fall out after just being shot once, actually it happened a lot. A change to another batch of the same load resulted in no problems.....

There are so many things to check. Your gunsmith could us a go, no-go gauge to make sure the headspace is okay. You might take the bolt apart and take a look at the end of the firing pin to see if it's nicely rounded and smooth.

You will figure it out. You sure have a winner by the way it's looking though!! Good Luck!
David

 

[Guy Miner]

Congrats on the great accuracy!

I owned a .300 RUM for about a year or so - when I got it, most of the folks recommended 95 gr of Retumbo and a 200 gr Nosler AccuBond - have to admit that the load worked really well from my rifle - nice to see that is holding true for others as well.

Nice shootin' :grin:

Regards, Guy

 

[JD338]

Teknys

You are there, congratulations on some nice shooting!

JD338

 

[GB300wm]

Teknys, you sure have a shooter. That's a great shooting rifle and great shooting on your part. Five shot groups really tell you where you are. :grin: :grin:

 

[Powerstroke]

Teknys

I was under the impression that the Remington Magnums didn't have an issue with the firing pin ???
I just had a .223 700 bolt bushed & the pin turned. What an incredible difference....

With that said, my .300RUM had a hard extraction with a full charge of Retumbo & the 200gr A-bond.

 

[Teknys]

I'll try to explain what I "think" is a crater. ONE primer out of the shots yesterday had a small rim around the firing pin mark. Almost like the primer pushed into the firing pin. Maybe I didn't get that primer seated into the pocket as well as the others. I use a RCBS hand primer.
I just haven't loaded anything this large before and noticed the little rim around the pin mark and wasn't sure if it was something to worry about or not.

 

[Guest]

That little rim is cratering. Whether or not it's something to worry about is another matter entirely. I'd take a second batch of these loads out and re-shoot them. If you get craters again (even one or two), I'd consider maybe backing off a smidge, say a half grain or grain of powder, and leave it at that. If you don't, it could have been a soft primer cup, a shallow seat on your part, or whatever else. If you get ejector marks on the case head, that's a bad sign for sure. If you're only getting an occasional crater, it could be pressure (very mildly) or it could be nothing.

 

[bullet]

I believe that will do!!!!!

 

[Woodycreek]

Retumbo and 200gr ABs seem to work ok in my Sendero II also :grin:

 

[SJB358]

Wow, that is a great group at 200 yards! Darn good shooting! Those RUM's are some powerful and accurate guns. They are really making a name in the LR game. Scotty

 

[JD338]

Woodycreek

Nice shooting.

JD338

 

[DrMike]

That will be good to tag any game you should every go after. Congratulations.

 

[6mm Remington]

I have heard nothing but how well the 300 RUM shoots in most rifles. What are your opinions as to why that is, those of you that have one? Is it that the case design and dimensions are just perfect for some reason and it simply just works, or is there some voo-doo with this cartridge?

I know there are many rounds out there that just have that magic something, and they work in just about any rifle built for them, and this appears to be one of those. You guys think this round will ever set a new 1000 yard BR record?

 

[bullet]

Very good indeed at 200yds

 

[FOTIS]

Good deal . Looks like you're on your way.

 

[Woodycreek]

I think maybe case design and luck on Big Green's part. Read it a couple of times about the 300 RUM not having a belt gives it some edge over other mags.