cart SHOPPING CART You have 0 items

Discussion Forums

Search forums
Forum Index > Rifles general discussion > Stringing shots - Sendero 7mm rem mag

Stringing shots - Sendero 7mm rem mag

16 Dec 2013
@ 05:10 pm (GMT)

Chris McKoy

Hi there, new to the world of hunting/shooting however I have purchased a new Sendero in 7mm rem mag which I sighted in yesterday and am having a few interesting issues.

Just some background on the rifle if it helps: 7mm rem mag Sendero, Hardy gen 4, weaver 20MOA base, z-rings, Vortex Viper PST 6-24x.

At 100m first 4-5 shots with 2-3 minutes between them strung 45 degrees diagonally upwards from right to left about 2cm apart, then settled and put 5 shots into a 2 centimeter group.

This was using Hornady 154g SSTs

My logic tells me that this has something to do with heating, however I need some advice on how to resolve it.

Any thoughts would be appreciated!



16 Dec 2013
@ 07:20 pm (GMT)

Nathan Foster

Re: Stringing shots - Sendero 7mm rem mag
Hi Chris, I see that you have just purchased a bedding kit thanks. Could you please give me a call during work hours, I want to go over this in detail. If I post here, I won't do the job justice.

For other readers.
Stringing from the M700 platform can be:

Throat burrs
Chamber end of barrel tighter than muzzle
SST bullet finicky (common)
Barrel temper in SPS but not usually Sendero.
Shooting technique, getting used to the rifle etc.

We (you) can generally sort each of the above without too much fuss, even dimensions. Heat treatment / harmonic probs can often be sorted with load tuning.

Always allow a good period of time / round count for the rifle to settle, load work, muscle memory. One of our readers had a .264 Win Mag built for him a while back in the U.S. M700 action, high end barrel cryo treated (to prevent harmonic problems / double grouping). I buddied the client and the smith. The client wanted the smith to adopt our bedding technique as opposed to the common plop and drop so this was my influence, introducing the smith to our bedding techniques. The smith was beside himself when after completing the job, the barrel double grouped. The rifle was accurate, but had a degree of double grouping. I asked the smith to sign off on the job and allow the client to shoot the rifle for a while, then re-asses later. That level of stress never gets us anywhere, best to step back for a bit. After a couple of months (handful of sessions), the rifle settled, the client settled, everything came together. No load work, just shooting the load the smith worked up along with a good cleaning regime and throat polishing regime.

Over the last year, I have tricked up two SPS factory rifles that did the same. Both came right over time. That said, I came across another 7mm rem Mag which looked to be rifled with a chipped tool resulting in malformed lands. One moment a tool can be perfect, the next it can have a chip- a chip so small that it can only be seen with a magnifying glass once it has been thoroughly cleaned of cutting fluid etc. If this chip is missed mid run, it will (or may) result in faulty barrels. So we find ourselves dependent on the regularity of tool inspections. Do we inspect each pass?, each hour?, each smoko break? Do we blame the apprentice for mistakes or the man shaking the stick and holding the time sheet or do we blame ourselves for often buying the cheapest rifles and setting low target price points for manufacturers.

Many of you will be familiar with this information which I covered in the first book.
16 Dec 2013
@ 07:40 pm (GMT)

Chris McKoy

Re: Stringing shots - Sendero 7mm rem mag
Many thanks for the helpful advice, I will indeed give you a call.

Here's hoping I can resolve this easily... on another note, another rifle - rem 700 ADL 7mm08 out of the box shot sub MOA so 1 out of 2 ain't bad!
16 Dec 2013
@ 08:27 pm (GMT)

Nathan Foster

Re: Stringing shots - Sendero 7mm rem mag
Sorry Chris, phone was going nuts earlier and I ended up deleting any messages on the phone by mistake a moment ago.
16 Dec 2013
@ 08:52 pm (GMT)

jason brown

Re: Stringing shots - Sendero 7mm rem mag
if it makes any difference, heres my short story with the same rifle and projectile (superformance factory load)
while shooting these they showed a lot of promise half inch promise, but there would always be one shot that turned it into a inch.
I thought it must be me, it was a big calibre for me and I figured im just not so good at controlling recoil.
then I started handloading the 154 projectile, nothing was really any better, I was thinking this big gun is hard to control. until I loaded for the amax. I soon realised, I can shoot not bad, and my rifle can make a good group.
so I guess mine just didn't like that projectile, so I gave up on them. and havnt looked back since.
im sure Nathan will help, but don't fret too much with that load, it might not like it also.


We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.