Powder choice, bullet, and group size.

aj427ci

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Colorado
Preface: I'm trying to put a load together for a 7mm-08 with 150 ELDX with Sta ball 6.5.

I bought a pound of sta ball 6.5 to try to get some more velocity over Varget or H4350 (powders I have on hand). I have found either the gun doesn't like the powder or the bullet. Best groups have been around 1.5 moa @100yrds. Would you give up on the bullet or the powder?
 
Been there and tried that. My 7-08 dislikes 6.5 staball. I tried it with 140 BT with about the same results as you. The velocity numbers really pull you in but over 1" groups are unacceptable for me.
I ended up using Ramshot big game but I think it's probably a little fast for 150's but then again I think varget is too fast for 150's to get decent velocity.
Edit to add: ditch the 6.5 SB and try the H4350
 
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I'm shooting Barnes TTSX 150gr pushed by Varget with consistent.75"-.5" moa. My X-Bolt did not like the 140gr TTSX. My primary load is 120gr Hammer Hunter pushed by Varget at 3000fps with .5-.65 moa consistently. It's been a long time with Nosler BT and AB out of opening day lineup with IMR4350. 2600fps is a mental issue for me when in fact out to 250 yards it's fine. This is what this forum will do to you 🤯
 
Preface: I'm trying to put a load together for a 7mm-08 with 150 ELDX with Sta ball 6.5.

I bought a pound of sta ball 6.5 to try to get some more velocity over Varget or H4350 (powders I have on hand). I have found either the gun doesn't like the powder or the bullet. Best groups have been around 1.5 moa @100yrds. Would you give up on the bullet or the powder?
As with anything else, YMMV. It would be best to find out what works for your rifle using different powders and charges, bullets, seating depths, etc., not other people's loads and rifles. I prefer the -M over -X.
 
Do you have any other powders to try with the 150s?

A few months ago, I started working up a load for my Sako 85 7mm-08. I have H4350, IMR4350 and RL16 on hand. Since this load will be used for cold weather hunting (below zero F) I wanted to stick with as temp stable powders as possible. So, instead of trying 2 or 3 powders with my chosen bullet, I tried RL16 with 5 different bullets. Two of the five bullets shot MOA or better. Both were flat based bullets. My rifle doesn't seem to like boattails.

So, there are a couple ways you can do this. Try several powders with your chosen bullet or try different bullets with the same powder. I still have two more bullets to try with RL16 but that will have to wait til next spring.
 
This is where QuickLoad shines.
I can run what-ifs with it to see which powder gives the following at once:
Max MV
at my case capacity
with .XXX of seated bullet bearing
At my barrel length
at SAAMI max pressure
at 100-104% load density

If the numbers validate across a chronograph, I don't blame the powder for poor results, as this is the best I'm gonna get.
Then there may be something less than optimum about the bullet w/resp to the bore/bore interface.
If full coarse seating testing is already completed, change the bullet,, Start over.
Otherwise back off the charge a bit, run full coarse seating testing, redevelop powder at best seating.
If results still suck, consider primer/striking testing.

IMO, a coarse seating test and a primer swap test are prerequisite to tuning.
Both can be done while fire forming brass to stable, and it can save a lot of tail chasing later.
Once below 1/2moa precision, do fine seating and neck tension testing for tightest group shaping.
 
Preface: I'm trying to put a load together for a 7mm-08 with 150 ELDX with Sta ball 6.5.

I bought a pound of sta ball 6.5 to try to get some more velocity over Varget or H4350 (powders I have on hand). I have found either the gun doesn't like the powder or the bullet. Best groups have been around 1.5 moa @100yrds. Would you give up on the bullet or the powder?
While I do not have any clue on how you loaded the ammo you have been shooting, especially since I cannot find any loading data for that combination. I would think, and remember, this is a Blonde thinking, that possibly there is no published data for this combination, at least I could not find any and whatever load you are using is not recommended by anyone. As such you are delving into uncharted and dangerous territory.

There are a few temperature stable powders out there. Here is an excerpt from Long Range Hunting from Feb 16, 22

Feb 16, 2022 — The Hodgdon "Superformance" powders are all designed to be pretty temp stable. Varget, H4831, H4350, H1000, etc. You can't go wrong with those for temp ...

Gunpowder charts for temp sensitivity and burn rates
Feb 16, 2022 — The Hodgdon "Superformance" powders are all designed to be pretty temp stable. Varget, H4831, H4350, H1000, etc. You can't go wrong with those for temp ...


Gunpowder charts for temp sensitivity and burn rates
Jan 26, 2021
Temperature stable powders | Long Range Hunting Forum
Jan 1, 2018
Stable powders | Long Range Hunting Forum
May 9, 2011
Temperature sensitive Powders | Long Range Hunting Forum
Dec 4, 2023
More results from www.longrangehunting.com

Delving further into this issue, I have not been able to find any published data for 7mm/08 with 150 gr ELDX bullets in the Winchester, Hornady or Nosler loading data that recommends Staball with the Hornady ELDX bullet. Even the Hornady manual lists Reloader 17 as their recommended powder with the ELDX. The other manuals recommend 7mm/08 with Barnes TTSX, Sierra HPBT and the Nosler Ballistic Tip or Partition with any variety of powders with H380 being the most accurate tested.

Now after all of this, the Staball HP loading data shows the 150 gr Barnes TTSX and Sierra HPBT as the recommended loads. Both are fine bullets that will do everything that the ELDX will do, and probably better. Of the two I have much experience with the Sierra HPBT across a variety of calibers and powders and that would be my preference.

I have found over the past 55 years of loading my own ammo most of the time that if I can't find the powder/bullet combination in any loading manual, especially that of the bullet manufacturer then, it's best to find another combination.
 

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