New Sendero - issues

[travisch]

I think I know what the problem is but wanted to float this past a larger audience.

I have a new Sendero in 300WM that I'm working a load up for at 100yds out of a sled. Best groups came with 185 Berger Hunting VLD seated .025 off the lands and 80grains of H1000 (3260fps) with 8fps as the max difference according to the chrono - sub 1/2 groups.
On Sat. I took it out to put on paper at 200yds but couldn't get it to group. I was prone on the rifle in a terrible position and I changed positions a number of times yet all prone (different cheek positions, shoulder anchor ect) which seemed to move the point of impact all over the place with each change I made to rifle hold. I expected some level of POI change moving off of the sled but it went from .5 moa groups at 100 to 5" groups at 200 and moved all around with each position change.
I believe my problem is the different rifle hold/positions but I didn't bring enough ammo to prove this to myself.
Thoughts? Does the hold affect POI this much?

 

[SabreCross]

I think I know what the problem is but wanted to float this past a larger audience.

I have a new Sendero in 300WM that I'm working a load up for at 100yds out of a sled. Best groups came with 185 Berger Hunting VLD seated .025 off the lands and 80grains of H1000 (3260fps) with 8fps as the max difference according to the chrono - sub 1/2 groups.
On Sat. I took it out to put on paper at 200yds but couldn't get it to group. I was prone on the rifle in a terrible position and I changed positions a number of times yet all prone (different cheek positions, shoulder anchor ect) which seemed to move the point of impact all over the place with each change I made to rifle hold. I expected some level of POI change moving off of the sled but it went from .5 moa groups at 100 to 5" groups at 200 and moved all around with each position change.
I believe my problem is the different rifle hold/positions but I didn't bring enough ammo to prove this to myself.
Thoughts? Does the hold affect POI this much?

Yes, it does. Very different rifle harmonics, (nodes) from sled to prone position.

 

[roninflag]

lead sled? i do not use one. i use a front pedistal and a rear sand bag.

 

[travisch]

Yup - lead sled. typically do not use one for sight in/dope development but for load development I find that its can be a much faster way to find a load with less rounds simply be removing the human from the math.

 

[Doublezranch]

I'm with Roy. IMO you have to shoot the way your going to hunt to get the best results. I was a huge believer of the lead sled until I realized that my POI was different when I was hunting than the gun being in the sled. We all have are shooting "qurks" that have to be instilled when shooting zero's or confirming drops. The lead sled also is very hard on equipment. Without allowing the gun to recoil properly, it puts lots of stress on everything. I've seen scope rings break off, scopes crack, and stocks boogered up. My lead sled still serves a purpose.....pictures.

 

[FEENIX]

I too use a lead sled (1st generation?); esp. in breaking in rifles (as it makes it very convenient in transitioning from cleaning to shooting) and load development. However, once I decided on the load, I refine it with my hunting set-up - normally with bipod/bipod buddy and prone without any problems.

It's hard to have a nice check weld and can't cradle the rifle well on the sled but I learned to adjust accordingly throughout the years ... it's certainly not for everyone ... but it works for me.

 

[HighKnob]

Anyone think maybe some bad scope parallax also?

 

[Korhil78]

I do load development and sighting in exactly the same way that I would be shooting if I were hunting. I use my bipod and rear bag and that is it. Its amazing how stable you can get in the prone position with a bipod and rear bag. Especially if you put a little pressure forward to "lock" the legs of that bipod.

 

[SabreCross]

Anyone think maybe some bad scope parallax also?

It could be that and a number of factors. I'd begin shooting from sandbags on the bench and on the ground (prone). That is the fastest way to rule out rifle harmonics.

 

[mark fox]

travisch. could be your line of sight in your scope has changed from on a bench to prone. this is a huge problem with many people and is even worse with poor quality scopes. due to paralex problems. what brand of scope and what power are you using.

 

[travisch]

Mark - scope is a vortex PST 6x24x50 FFP

 

[mark fox]

vortex is a ok scope should not be the problem. I would check your paralex and adjust in prone. also get the gun up higher off the ground with your harris so that your line of sight is better in line with center line of scope. This will help on guys like me a little over weight and older less flexable. 5 diffrent people shooting the same gun in prone can be off as much as 3" at 200 yards. The way you look threw the scope can make a huge diffrence.

 

[Rick Richard]

I don't think it has anything to do with parallax from 100 to 200 yards. If further out, maybe some but not as much as you indicated the change was.

I would be looking to see if anything is loose first, then go back and verify again. Also, shooting from prone and using a bipod will make a change in POI if you added a bipod.

 

[moombaskier]

My $$$ is on parallax. It doesn't take much to be off at even 100-200yds. Cheek weld and how you hold the rifle HAS TO BE THE SAME every shot or your groups will open way up! I also use a lead sled for load development and to give me an accuracy base, then I work on my shooting form to try and out shoot it.