Strange occurrence at range today

[Big Norm]

I purchased a used Savage 116 in 7mm mag with factory brake. LGS installed a Millett TRS-1. I loaded up 20 rounds for a ladder test and 10 rounds with 61gr imr4350 to sight in with.

2 shots at 25yrds adjusted windage and elevation.

Moved target to 50 yrds

3 shots at 50yrds touching in a lateral string.. ( Exactally what I wanted to see)

Moved target to 100yrds.

3 shots 7 inches high 3.5 inches high and group size 3+inches.

Moved back to 50yrds, 3 shots .680 group. Back to 100yrds 3 shots 2.8 inchs
WTF!!!!!!!

Brass is once fired, full length sized, trimmed to length, 61gr imr4350 (medium load) cci mag primers nosler ballistic tip seated .10 off lans measured with Hornady comparator. Gun on bench with front and rear bags temp 77° [no crono to measure velocity]

Where do I start with problem solving, I have only been reloading for a 9mths so my knowledge is not as extensive as others... I have other powders to try but not sure if this is a gun problem, ammo problem, or scope problem...

I havent ruled out scope but my 50yrd groups are consistant when I mobe target so im kinda stumped.. any troubleshooting help is appreciated!

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[SJB358]

I don't think you have much wrong with anything to be honest. A group like that at 50 really doesn't mean too awfully much. While good, at 100 and even 200 or more is a little bit better at judging the accuracy of the load. I can't tell what you mean by your first group being 7" and 3.5" high and a group size of 3+"?

If you could throw up a picture or give us a better idea of what is happening, it might be easier to diagnose.

Also, what BT are you using?

 

[Big Norm]

Sorry about the typo.. I sighted in at 50yrds at dead center of target. At 100yrds I has a group 7in higher on the target than the 50yrd group and it spread to about 3 inches.



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[SJB358]

The group being higher at 100 yards is completely normal. Since you zeroed at 50, it makes complete sense.

Now, your actual group size. I wouldn't rule anything out. Is your ladder a powder charge ladder or a seating depth ladder?

Either way, I would likely do the powder charge first, then find the seating depth. Your groups will probably tighten up as you increase to more PSI's.

 

[Guest]

I'm with Scotty. You don't have enough data in hand to call it bad, yet. Work up with a chronograph and find the velocity you want. Then use seating depth to tweak the load to group. Find a load in your desired velocity range that is around 2-3" at most, and work from there. I took a >3" Nosler 130gr E-Tip load in my 270Wby down to <.7MOA with seating depth tweaking, so big improvements can be had that way.

 

[Big Norm]

I guess I was thrown off because I have not had such a bug difference in point of impact between 50 and 100 yrds.. there is usually a 2 of 3 inch rise in impact but never 7inches

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[Oldtrader3]

That would indicate to me that you loads are too low pressure Start a little higher with the load and it should shake out these issues.

 

[Big Norm]

Nosler load data is 59-63 grain, I hit it dead in the middle at 61gr. Book rated this load at 3138fps, I

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[OU812]

The group being higher at 100 yards is completely normal. Since you zeroed at 50, it makes complete sense.

Now, your actual group size. I wouldn't rule anything out. Is your ladder a powder charge ladder or a seating depth ladder?

Either way, I would likely do the powder charge first, then find the seating depth. Your groups will probably tighten up as you increase to more PSI's.

Good advise Scotty. I always run my powder up first and adjust seating if needed.

 

[Guest]

If you did not chrono the load, don't take book velocities to be anything like gospel in 7mmRemMag. For whatever reason, that cartridge is just about the most variable in velocity for a given powder charge I've seen when handloading. I've come to believe it's due to high levels of variation in chamber cutting for these rifles, across multiple companies. I've seen visible differences in shoulder length on 7mmRemMag brass between different rifles. By visible, I mean clearly obvious with the naked eye. Good thing the big 7 headspaces on the belt or somebody would get hurt.

I'd encourage you to chrono the loads. The only 7mmRemMag I've owned out of the various ones for which I've worked up loads, was cut with a long shoulder, and velocities were fully 300fps below what the books listed for the powder charge. Accuracy was in the toilet on that rifle, too, but for a variety of reasons. You may well be dramatically under that 3100fps published velocity. If you don't have a chronograph, get one.

 

[Anonymous]

I'd go scrounge up a box of quality factory ammo... you have too many variables (used rifle, new scope, a ladder series of loads, and new to reloading)- you need a benchmark or you simply have no idea if what you're doing is working without a lot of trial and error...

Something common like Remington Core Lokt or Federal Blue Box that generally shoots well- that should tell you if the rifle is shooting poorly or if the ammo is the issue. If the rifle shoots factory into a reasonably good group then work on your ammo. If the rifle shoots a factory load the same level of accuracy- work on the rifle

 

[WYcoyote]

I would do as hodgeman suggests above and if weird things are still going on I'd start looking at the mounts and scope.

 

[FOTIS]

Set up a ladder at 200-300 yards and go for it.

 

[SJB358]

Set up a ladder at 200-300 yards and go for it.

I am with Fotis on this. The further the better. Seems like since I have started shooting longer for load development, I haven't had quite as many false-positives as I do shooting at 100. Plus, then I know how they are working at distance as well.

 

[Mud]

Does the bullet weight match your barrel twist?

 

[Big Norm]

Mud: I am using 150gr ballistic tip in a 23in 1-9.5 twist barrel....

Hodgeman: that is exactly what I will do when I can find some factory 7mm that isnt $40+. A box... checking out Wally world and they still have mixed variety but still limited...

Fotis: that is my intention, but I dont have a place locally that I can shoot out past 100 so I will have to wait till I can get to my hunting land 2hrs away and I have 120 acres of cow pasture I can stretch it out on...

I have Retumbo, IMR 4350, RL22, IMR 4064 and 4831ssc to try as well as nosler 140 and 150gr AccuBond and ballistic tip and berger 168gr vld hunter

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[Big Norm]

SJB358 & Budyam, after doing more reading today on various forums, I think the low pressure may be a viable answer, after looking at the cases I notices soot around the neck which from what I have read is a sigh of low pressure due to brass neck not fully expanding.. this was the first time I fired this brass in this rifle, ill be neck sizing the next set of rounds and trying some of the other powders I have listed when I find some good load data for them.... (RETUMBO) to be specific!

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[Big Norm]

PROBLEM SOLVED! I guess its kinda my fault but I thought I could trust the LGS I bought my scope from to mount it properly.

After receiving advice from others I bought a box of ammo and went back to the range for more shooting and opened my hard case, set up to shoot, attempted to adjust magnification and the whole damn scope turned on the rings and the Leupold rear mount with the clamp screws had come all the way loose, the front twist in ring was misaligned and NO loctite on any of the screws... SMDH!

Took me all of 30 mins to take it all apart and put it all back together properly! Shoot great!

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[Guest]

If you want something done right, you'd better do it yourself, when it comes to optics. Glad you solved the issue.

 

[Big Norm]

Yep, another lesson learned!

Thanks everyone!

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