R700 7mm rem mag Sendero Accuracy Issues

[I Am Hero]

Ok so I have just about gone nuts over the last 2 weeks trying to work up a load for my R700 7 mag Sendero. Here are the specs:

R700 Sendero in 7mm Rem Mag
26" 1:9 barrel with Fox River Brake (~1000 rounds fired now, 900 by previous owner)
Spiral Fluted Bolt
Badger Bolt Knob
Badger 20 MOA Rail
HS Precision stock with Accurate Mag bottom metal
Burris Xtreme Rings
Millett TRS-1

Dies:
Lee Neck Sizer
Lee seater
Lee crimp die

I am working with 3 different types of bullets:

- 139 gr SST
- 154 gr SST
- 168 gr SMKs

I have worked up a 1 MOA at best load with the 139s and 168s. The 154s I recently started on. I will get something along the lines of this picture quite often:

1st shot was cold bore high (thought maybe this was a bad flinch after shooting my 223)
2, 3, and 4 were touching low
5th shot was high left



I am using the following powders with listed results:

Retumbo (pretty good results with loads near max as listed in Sierra's and Hornady's book)
H-1000 (probably the best results I am getting so far)
RL-22 (I have heard that this is most common for 7mm and 300 win mag...it straight up sucks with every load I do).

I have tried minimum loads at factory length and 3.425"
I have tried medium loads at factory spec and 3.425"
I have tried max loads at factory spec and 3.425"

The 3.425 load seems to provide the best accuracy, but the bullet actually wobbles a bit in the neck because it is so far out. I tried backing it 3.330 and the accuracy went to shit.

With the exception of a few barely sub-MOA groups with the 139s and 168s, the accuracy depicted below is quite common:






So my question is, what the hell am I doing wrong? Factory PSP Core-lokt seems to group just as good as my best hand load. I might buy a box of Hornady 154 SST factory loads to try and figure out if it is me or the rifle. Am I expecting too much from a factory Sendero? I have owned a R700 SPS-V in 308 and it touched holes with my 168gr loads after I upgraded the stock, so I didn't think the rifle has poor accuracy. I have a custon 223 and 338 but was hoping to find a middle of the road caliber (.308 is all service rifle for me) without spending the money on a custom gun again.

 

[Recreational Shooter WA]

I find it useful, at least initially, to choose just one bullet, one powder, and one primer and work up an OCW load. This avoids information overload!! A few google searches should give you some good bullet/powder combos.

If you really want to know if the rifle shoots, buy some premium ammo and let a couple experienced shooters shoot it. Should let you know if its you, the rifle, or the reloads.

And as always, check to make sure everything is tightened correctly. You can torque that HS stock to 65 in/lbs.



OCW Overview - Dan Newberry's OCW Load Development System

 

[briscoetab]

Don't know if this will be useful or not but you said you load the bullet to factory length, how far off the lands are you? If I load my rifle to factory length it won't group at all either. I think I am .2" longer than factory specs on my load. It stinks because now my rifle is single shot but shot .24" 3 round group and .72" 5 shot group.

If your loading to factory specs you may just have way to much jump. I would try seating longer and see if this helps. I always start barely touching lands and find a good load, then work with seating depth off of that.

 

[Niles Coyote]

69.7g H1000 under a 168 smk in winchester brass for right around 2875fps in my R700 Long Range. That got them to touch at 100 yards. I have not taken it out long yet. I am .020 off the lands IIRC.

 

[xringaccuracy]

Get an OAL length guage to start. Forget factory specs as they are made to shoot / chamber in anything. Build the ammo to fit your gun. You may find you are past mag length to reach the lands.

 

[Natty Bumpo]

Good advice regarding have someone else shoot the rifle, get an overall length gauge, try OCW load development or try some match grade ammo. Another issue may be that you believe everything here on Sniper's Hide about how everybody's factory rifle shoots sub-MOA "as long as I do my part" or "with the right handload". While Senderos have a reputation for accuracy, not every rifle is capable of consistently shooting within one MOA. Keep trying, but what you're getting may be as good as it gets.

 

[I Am Hero]

Alright so I did the following load:

70.1 gr Retumbo
New Winchester Brass
Federal FGMM Primers
Brass trimmed to 2.490"
OAL was 3.425"

Loaded it up and shot just under an inch so I figured that was pretty decent. Loaded the EXACT same load the next day and it was up near 1.5-2 MOA so I can't have that kind of accuracy inconsistency.

Sunday I worked up the same load but seated at 3.525" OAL and did the old match soot technique, still no marks from the lands (now mind you factory load is 3.290). The bullets were finally touching:




I thought this was all great and dandy so I tried the exact same velocity load (per Sierra's book) with H-1000 and RL-22. The H-100 was garbage, 2" at best. The RL-22 was practically touching until the 4th shot went way off to the right.

I shot without a brake thinking that this might have been part of the issue and there was no accuracy improvement whatsoever; perhaps even some loss of accuracy.

So my next question is: Why is it that H-1000 and RL-22 produced crap loads at the exact same velocity that I loaded the Retumbo to? I am going to try the Retumbo load again but because this is my friend's rifle that I am loading for I would much rather use the H-1000 and RL-22 that he bought instead of my Retumbo that I use for my Lapua. Thought about buying some 4831 and RL-19 to try since people and sierra seem to fancy those powders as well.

I'm just wondering if I should make him buy some Retumbo powder and stick to that load or try for some others. He got sick of trying so that is when I took over and I am just about sick of it as well. My .308, .223, and .338 lapua were all spot on sub-MOA with my first loads I cranked out.

Now obviously I should just chrono these myself but it's a little annoying when Lyman and Sierra say the following:

Lyman says 2 things:
65.5 gr H-1000 is 2645 FPS
Max load is 72.0 gr H1000

Sierra says 2 things:
65.7 gr H-1000 is 2800 FPS
Max load is 68.3 gr H1000

It's frustrating that they can be so different for the exact same 168gr load.

 

[chaser_2332]

my factory sendero gave me fits with retumbo, switched to h1000 and it settle in nicely. I was shooting 180 bergers

 

[29aholic]

Yeah I think I'd try heavier bullets myself with that rate of twist.

 

[onethousandmeters]

It's been a while, but my load was with 4831sc pushing the Hornady 162gr AMax. It was a few years ago, but that was the best load for me; usually 1/2 MOA on my Sendero. Glad you got your group size down, and began working with one aspect of the reloading at a time. Good luck and enjoy as the 7mm Rem Mag is a great cartridge, and I always liked my Sendero when I had it.

 

[Graham]

You've got 1000+ rounds through a factory barrel, which is headspaced at the belt. 1.5 MOA is acceptable under those circumstances.

 

[Morale_Gear]

You've got 1000+ rounds through a factory barrel, which is headspaced at the belt. 1.5 MOA is acceptable under those circumstances.

Agreed. That's not bad for a 7mm Mag barrel with that many rounds through it.

 

[tylerw02]

I'd imagine you're about at the end of the barrel life of a 7mm Rem Mag.

 

[my human host]

I'd have it borescoped before using up any more expensive components. I'm guessing there's some pretty severe fire cracking in that bore.

 

[I Am Hero]

Made me wonder if I was getting near the end. I was a little wary buying one at 900 rounds but I at least got a really good deal on it. Would have paid that much for the action and the bolt work that was done to it (fluting and new knob).

The inconsistencies in the exact same load made me wonder what was up. Was hoping I didn't have to drop $800-900 to get a rebarrel and true done but it might be about that time unless I decide 1.0-1.5 MOA is acceptable.

 

[redneckbmxer24]

The last few posts are spot on, that barrel is nearing the end of its life.

 

[hessian]

My experience with Sendero in "91 or thereabouts was that accuracy was wholly dependent on OAL. My loads were all at 3.55". Powder and cases meant nothing.It did best with AA 3100. Luck

 

[LoanHarvey]

I have been trying to find a good load for my R700 24" 9.25 twist as well, using Berger 168vld's. Could not get RL-22 to shoot. What I did get to shoot just under 2" at 200 yards, was
H4831 63.8gr seated .020 off the lands. Those were only 2814 ft/sc. So I wanted a better group and more speed, so I tried
Ramshot Magnum 71.5gr seated .010 off the lands and got a 2" group at 200 yards, and those were not chrono'd. Still searching like you are.

 

[I Am Hero]

Yea I might just get this sucker rebarreled and start this whole process over again. I even tried 3.550 (really can't go out any further or the bullet will be loose in the neck) and with retumbo I started getting black soot around the belt. That seemed like an issue. The H1000 and RL22 loads I worked up to that length came out clean.

H1000 was hole on hole first two shots and last three, but one inch apart at least. .. Grrr

RL22 was most accurate but a very sloppy one inch group.

Retumbo sucked balls. This was always my best powder but these results were 2" at 100.

 

[gewehr]

You could try tubb's final finish lapping bullets. I have seen 4 rifles with problems like you have shown have 1/3-1/2 Moa improvement after trying it. I have also seen 2 shoot the same after the treatment, either way it's not an expensive fix that may help


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