New to reloading. Need a little help before tomorrow.

[shooters]

Hello. I've spent a few hours searching and found most of the answers, but still have questions. I have a factory 300 RUM Sendero ll. I just started reloading and I am completely lost on things like, bumping the shoulder, only half neck size, only partial full length resize, etc.... It seems very easy for me to just full length, trim, etc... and of course checking wall thickness, reaming, etc.. But whether or not to full resize or neck really confuses me. I realize its harder on the brass to always full length, but it seems there is a lot less I have to check and worry about. Besides, what is a bag of brass every year or two. No biggy. If I had a Shilion barrel, McMillian stock, trigger, etc.... well, a custom rifle, then I would for sure be using fire formed brass and doing everything I could to gain the most accuracy as possible, but........

......is there "that" big of a difference in a "factory" rifle to go ahead and only neck size and using fire formed cases over using full resized brass? I enjoy shooting out to 7&800 yards, but only on targets. I'm not near good enough or confident enough to take a shot at an animal at that range, but am out to 500 yards. If I were to shoot at extreme long range, then I would be doing everything possible with my brass to gain the most accuracy as possible.

I have lots of fired brass and would like to use it, but I'm unsure on what to look for in reloading it beside trimming it. I don't know what I'm reallying looking at when looking at the shoulder, the neck wall thickness, etc. How many reloads can I load before worrying about the shoulder moving forward, ejection broblems, wall thickness? I would like to use the fired brass, but have no real knowledge on it. I've preped all the brass as far as weighing it all, deburring, primer pocket uniformidy, etc... If there is not that big of a difference in formed brass and full lenghth, then I'll full resize. If there is a thread somewhere on here and someone can point me in the right direction, thanks. Any help would be great. I need to load tonight to sight in tomorrow to finish off the last 3 days of season.
Thanks for the help.

 

[shooters]

Sorry, I put this in the wrong section. If someone could please move it. Thanks

 

[royinidaho]

If the fired cases were fired that specific rifle, assuming they were not high pressure, that is, the fired cases will chamber with no or only very very slight pressure, I'd simply neck size.

I'd also neck size sufficiently that the body of the cartridge is clearly touched, determined by looking at die marks. This is 'supposed' to assist with alignment.

I neck size until chambering pressure is noticeable, then FL size. I have used this process on a good shooting 270 Win, with the same 60 cases over more than 30 years.

Hey, works for me.

I do the same thing with extreme magnums though a bit more precise.

 

[WildRose]

If the fired cases were fired that specific rifle, assuming they were not high pressure, that is, the fired cases will chamber with no or only very very slight pressure, I'd simply neck size.

I'd also neck size sufficiently that the body of the cartridge is clearly touched, determined by looking at die marks. This is 'supposed' to assist with alignment.

I neck size until chambering pressure is noticeable, then FL size. I have used this process on a good shooting 270 Win, with the same 60 cases over more than 30 years.

Hey, works for me.

I do the same thing with extreme magnums though a bit more precise.

PRetty close to what I always have done. Neck size three or four times, then full length resize.

When I do the full lenth resize, I measure by looking at the neck marks and adjust down to where I can see it's just making contact at the base. This isn't quite a "full length" resize bringing it back to factory SAMMI Spec and keeps it "fire formed" essentially.

Note, if you are going to use the ammo in any other rifle it may/may not work properly.

 

[shooters]

I give thanks on Thanksgiving to anyone willing to help me out .....in a hurry. Just went to range again.... Dope chart says to be dead on at 275, I should be .5 inches high at 50 yards. I am. 3 rounds, same hole. Cleaned gun and removed all copper. Went to 100 yards. Chart says 2.5 inches at 100. 3 rounds pretty much same hole. All touching. Cleaned gun. 200 yards, suppose to be 2.7 inches high. I am ALL over the place. High, low, right, left??? Cleaned gun, tried again. Same thing. Like a 6 inch group. Cleaned gun, went to 300 yards. Suppose to be 1.5 inches low, was 5 inches low, 9 inches low, 5 inches left, 7 inches low. Just all over the place. Loaded to exact book specs for 200 grain Accubond, 94gr Retumbo, 2.840 brass Rem brass, Fed 215 primers, full resized. 3.600 OAL. I have never built loads before, so I'm so lost. Is this a scope issue? Rings or base? Load issue? The scope is the top Sightron Slll 6-24x50 with Seekins rings and base. 300 RUM has a Kirby break on it, so I'm not sure if the scope can't handle the forces or what. I would have thought that if I could have 3 rounds touching at 100 yards, then the gun would obviously be shooting well out to longer ranges. Is the bullet not stabilized yet? Is this what its like when loads are in need of tweaking? I would have assumed that at 100 yards and that kind of group, it was a good load. I'm shooting off a lead sled. Does that effect accuracy? I am 100% sure it is NOT me. Recoil/noise does not bother me even though there is zero with Kirby's break and the lead sled. That thing is rock solid on target. Please help. Does this sound like a load issue or a scope/rings/mount issue? Thanks.

 

[kwp]

I would definitely start by checking your rings and bases, sounds like something came loose.

 

[mjls4me]

if you are using this as a hunting rifle and will be using these loads for hunting full length size them as for what your brass looks like if theve only been fired once from your rifle their probably fine i always use the trim to length i have a 300 ultra that shoot ity bity bug hole groups and i always trim and full length size if you find brass that looks like something is wrong with it then your probably right better to err to the safe side as for as by tommorow goes you cant learn it all in one a hands on mentor is the best way to learn what to look for hope it all works out for you

 

[mjls4me]

if you do have base and ring problems the ultra mag is not very forgiving on regular run of the mill rings and bases i suggest a solid picatinny rail with aheavy set of rings with across bar in them nightforce has some of the finest mounts made and always use lock tight the mounts are just as important as the scope or rifle ive seen people spend 1000 for a rile and 700 for a scope and put a 40 dollar set of rings and bases on it this is a recipe for trouble

 

[shooters]

if you do have base and ring problems the ultra mag is not very forgiving on regular run of the mill rings and bases i suggest a solid picatinny rail with aheavy set of rings with across bar in them nightforce has some of the finest mounts made and always use lock tight the mounts are just as important as the scope or rifle ive seen people spend 1000 for a rile and 700 for a scope and put a 40 dollar set of rings and bases on it this is a recipe for trouble

Have Seekins picatinnny rail and rings. Was $250. I was told by most of the guys on here they were at the top of the top. Don't think they are the cause. I tore it all apart and reinstalled to torque specs. All looked. Good. Just can't figure out why I'm getting huge groups from 200 yards and out.

 

[woolecox]

I have a custom 7mm Rem Mag that will not group with a clean barrel. It shoots best 5 shot groups (.5 MOA) after 2-3 fouling shots. It is a huge difference in accuracy with this gun. I have two others that don't seem to care.

May be obvious but give it a try.