Thread: My 260AI Load Development Begins

Got some promise then, no drizzle and not much wind at my place.

Bit of a breeze here but trying to clear. 1" would be marginal for 1000yards?

Possibly, once you have a load with promise at 100, then try 300. Some loads that group OK at 100 group even better at 300 plus. (ie 1" at 100 but 2" at 300) I can't ( and I don't think anyone else can) explain how that works but it does, sometimes.

Originally Posted by stug

Possibly, once you have a load with promise at 100, then try 300. Some loads that group OK at 100 group even better at 300 plus. (ie 1" at 100 but 2" at 300) I can't ( and I don't think anyone else can) explain how that works but it does, sometimes.

Bryan Litz covers why in one of his books. I cannot remember the exact reasoning - it took several sentences to explain. A point he also makes is the other way around - a tight group at 100 yds doesn't guarantee that at the further distances the group size will be proportional to the 100yd group, particularly if the ES is high. So like you say essential to test further out. Also well known with boat tail projectiles being more stable once further out.

I always thought we just shoot better further out

Originally Posted by Fisherman

I always thought we just shoot better further out

As normally you are aiming at a smaller dot % wise


The equal of a 2.5 inch dot at 1000yrds is a 1/4 inch dot at 100yrds


Start using a 1/4 inch dot for a 100yrd aimpoint and see what happens to your groups with an accurate rifle

Aim small hit small

Originally Posted by Fisherman

I always thought we just shoot better further out

As the gun operator if you cannot shoot close up how can you shoot better further out?

Wow what an interesting morning. Finally stopped drizzling and more importantly blowing. First up shot the 260AI with the seating depth test. Started with the extremes - 2.803" and 2.840"...the latter went into 0.4". The rest didn't show much variation.

In between sighted my 7mm08 with suppressor on. 120gn 3018fps. Looks about 0.25"...and has shot that before too.

I use to not bother with seating depth. But got caught out shifting from a Remington Sendero to HS Precision SPL. Both shot the same load into 0.5" but then on a hunt the HSP left the bullet stuck as an unfired round was ejected. Lesson 1: Seating depth is impt. Lesson 2: cycle each hunting round before goinf on a hunt.

Well pleased now as really concentrated today as I have not been happy at all with my shooting lately.



And my 2 beauties.



I did full length size but noticed a couple of rounds tight to chamber? Length is fine. I notice when FL sizing there seems to be very little effort required compared to other cals....put this down to very close chamber and die??



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PS the reason for the big shift between the 1st and 2nd 7mm08 sighters is I was being generous with the adjustment and also forgot the Z6i is in cm not MOA. D'oh.

As requested
260AI


7mm08

Thanks @mikee

Had a play with my Ackley and FF some cases with projectiles. I have not even tried it with this barrel before so was pleasantly surprised how well it went.

129 gr interlock hard into the lands shot pretty well at 2740ish. A lot of mirage today with the heat. So surprised they went as well considering my eyesight.



Not bad ES over 3 rounds. Jumped out to 23 over the 9 shots but I shot them faster than I would normally


Didn't form a perfect shoulder so could probably up the load a bit.


Certainly good enough to hunt with.😆

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Geez...all this 260 Improved stuff has finally rattled me enough to get all my parts off to the gun plumber today Only been sitting on it for a year or so, but other guns have been absorbing my energy till now.

Keep up the progress reports, it may save me some work

@R93 nice shooting, what powder & load did you use?

43 grns of 2209.
Pretty sure it can handle another grain at least as the shoulders only formed about the same as I can get without projectiles.

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