260AI...picture heavy

[LongRange]

Im going to try H4350...RL-19 and RL-17 in that order with CCI BR2s thursday.

[upSLIDEdown]

Guy I shot with once is running a 260ai with RL-17 pushing 140 hybrids 3045fps. Not sure what his charge is though. It's a tack driver too.

[LongRange]

if i can get 2975 to 3000fps accurately with a consistent load i would put all of my standard 260 stuff on the back shelf to collect dust while i figured out how many rounds i could get through a barrel before it went south...i have no doubts its doable just need to find the right combo and in this barrel its not going to happen with 4831...i MIGHT be able to smash another .5 to 1g in a case but compressed loads are a PIA when seating bullets.

ill load up 3 rounds each with the powders listed above working up in .5g increments and since i cant find much info on those powders in the 260AI im going to look back through my 260 data and start at the max charge ive shot through the standard 260...well maybe a little below LOL!!

[Dewey7271]

Seems like there are a couple sweet spots I've found in mine. 2910-40 and around 3020 if that helps?

[LongRange]

i tumbled the 58 cases i have formed(had a little seepage on one yesterday so i tossed that case)sized all the necks and took some measurements...my cases are .002 shorter than the measurements i got from Dewey as far as i can tell so i canceled the head space gauge i had ordered for now...i dont want to spend anymore money on this project until i figure out if im going to stick with it or not.

the necks(or case OAL)was all over from 2.0185 to 2.023 so im going with 2.018 as the trim length...the shoulders are right at 1.672 using a hornady shoulder gauge and the cases chamber snug just how i like them to..the chamber is at .298 as the fired necks are .297.

the winchester brass seems to be holding up well at this point except for the one case that had a little gas seepage yesterday which i think was just a bad case as the primers where no where near flat and i shot 9 more rounds that were the same with no issues.

[LongRange]

Seems like there are a couple sweet spots I've found in mine. 2910-40 and around 3020 if that helps?

i wont be happy at 2910...yesterday at .020 off the lands i was at 2932 and was thinking its "ok" but a little more would seal the deal but its not gonna happen with 4831 for me...the groups i posted arent acceptable for me either...im not expecting a 1 hole group out of this barrel but its got to be something tighter than those to peak my interest LOL.

[WinnieTheBoom]

Have you done any testing for pressure signs on a standard 260? If you can get 2,900 fps out of it, I think it'd be hard to justify the AI... Just keep in mind that all these guys saying they are getting up to and around 3,050 from an AI could be doing so under different conditions, different chronographs, different barrels, etc. Just seems like those velocities might not be the norm.

Take it with a grain of salt, just thinking out loud at this point.

[LongRange]

i agree and the reason im doing this as cheap as i can and why i like doing my own testing on things...i found several things over the years ive heard or read that when put to the test dont hold water in the real world...ive never done a trace/strain type pressure test on my 260s and im sure my loads are over book pressures but i get 10-12 loads on my brass so if i am over max its not a lot.

ive seen 5 142g smks at 3050fps out of a standard 260 with .220 free bore and a lot of RL-17 but the brass wasnt real happy about it...the chrony i shot them through is always about 20fps fast so in reality they were probable closer to 3000-3020.

[WinnieTheBoom]

Yeah I mean when you think about it, the increased capacity of the AI cartridge should in theory give you better velocity shooting the same or similar projectiles, but if a standard 260 is going to give you 98% of AI performance with less headaches, it might not be worth the hassle.

Those are some pretty impressive results with the 260... If you're able to maintain mid 29s with the standard 260, and the brass holds up for 10ish firings, I'd say that's your ticket. Interested to see what you find as you continue your testing.

[LongRange]

Yeah I mean when you think about it, the increased capacity of the AI cartridge should in theory give you better velocity shooting the same or similar projectiles, but if a standard 260 is going to give you 98% of AI performance with less headaches, it might not be worth the hassle.

i agree with this 100%


Those are some pretty impressive results with the 260... If you're able to maintain mid 29s with the standard 260, and the brass holds up for 10ish firings, I'd say that's your ticket. Interested to see what you find as you continue your testing.

my loads in the 260 right now are not at 2900FPS...in one im at 2830 to 2840 out of a 26" barrel the other is at 2810 to 2830 out of a 28" barrel and these loads are very accurate and very easy on the brass...in the 28" barrel ive got 50 pcs of brass i was shooting in another barrel that had 6 loads on them and i have 7 on them in the newer barrel.

its been awhile since ive shot fast but at 2900fps in the standard 260 the brass life drops to 6 to 8 loads before the primer pockets are real loose and for only a 60FPS gain i decided it wasnt worth it...at 3020(or so)FPS you get one load on new lapua brass and i can guarantee that its at dangerous high pressures as it takes 15% over book max to reach those speeds.

in the first 28" 260 shilen barrel i bought(the one i AId in this thread)i had 2800 recorded rounds through it...i never shot anything over 2770 and used the same 100 pcs of lapua brass...the next barrel i bought is when i started seeing how far i could push it...i got scared at 15% over LOL!!

[WinnieTheBoom]

I thought that seemed high for the standard .260, LOL. Even if you could stay around 2,850+ with 10ish firings on the brass, I'd say that's still pretty good and that you're really not gaining much if you're only getting 2,920s with the AI. Probably not best to be running 15% over max, as that's definitely starting to get dangerous... if you're losing the primer pockets on virgin Lapua brass after 1 firing I'd say that's a tell tale pressure sign :(

Any idea what the performance threshold is going to be where the AI becomes worth it? 100+ fps difference maybe?

This is very similar to my situation... I bought a .338 Lapua 110 and considered going to .338 Edge when I shot my first barrel out of it. The more I thought about it, the less it made sense as I was already setup to shoot the Lapua (brass, dies, etc.), and the 50ish fps difference in velocity didn't justify the costs of switching. I guess mileage is going to vary for everyone, but to me, it's always best to keep things simple.

[Dewey7271]

FWIW, I have a bias in that I really like AI cartridges. Not that I'm a hotrod in particular, just like the way they look, lack of trimming, and brass life (at least so far in mine). Besides, they just look like they're going 3000 FPS sitting there.:o
My rule of thumb, outside of the no need to trim reason, is 5% plus improvement. Nothing etched in stone, just a personal thing. So if I had a regular 260 at 2800 or so, I'd want the AI to show me something like 2940 or so. Some of them do a lot more (like the 250 AI for example) but around 5% or more does fine for me. My 250 AI brass is on 7 or 8 now with no loose pockets as yet.
YMMV.

[upSLIDEdown]

Just load up some RL17 and get on with it!! All this chitterchattering is wasting valuable time! Haha

[LongRange]

I thought that seemed high for the standard .260, LOL. Even if you could stay around 2,850+ with 10ish firings on the brass, I'd say that's still pretty good and that you're really not gaining much if you're only getting 2,920s with the AI. Probably not best to be running 15% over max, as that's definitely starting to get dangerous... if you're losing the primer pockets on virgin Lapua brass after 1 firing I'd say that's a tell tale pressure sign :(

agree...this was when i went into full test mode with the 260 and my 300wm a few years ago because as ive said i only believe half of what i see and none of what i hear LOL...i decided to see how far i could push both rifles a few years ago so i would know first hand what was what instead of hearing ppl parrot things they have heard.



Any idea what the performance threshold is going to be where the AI becomes worth it? 100+ fps difference maybe?

i dont know as ive just started with this but for me...if i can get 2975fps ill be very happy and just happy with 2950...but then comes the question of barrel life...which i have heard and read several different opinions on as well....i dont know for sure but im going to bet 1500 to 2000 rounds will be about where things start to go south out of a new 260AI barrel.
if i can not get an accurate consistent load at 2950+fps i will not pursue this an farther than this because i can get 2850 out of a standard 260 that will shoot bug holes and like you i have a lot of money tied up to load for 260.


This is very similar to my situation... I bought a .338 Lapua 110 and considered going to .338 Edge when I shot my first barrel out of it. The more I thought about it, the less it made sense as I was already setup to shoot the Lapua (brass, dies, etc.), and the 50ish fps difference in velocity didn't justify the costs of switching. I guess mileage is going to vary for everyone, but to me, it's always best to keep things simple.

im right there with you and why im doing this cheap.



FWIW, I have a bias in that I really like AI cartridges. Not that I'm a hotrod in particular, just like the way they look, lack of trimming, and brass life (at least so far in mine). Besides, they just look like they're going 3000 FPS sitting there.:o
My rule of thumb, outside of the no need to trim reason, is 5% plus improvement. Nothing etched in stone, just a personal thing. So if I had a regular 260 at 2800 or so, I'd want the AI to show me something like 2940 or so. Some of them do a lot more (like the 250 AI for example) but around 5% or more does fine for me. My 250 AI brass is on 7 or 8 now with no loose pockets as yet.
YMMV.

as ive said i may be just expecting to much out of all of this but it will scratch the itch ive had to try and find out for myself LOL!

[LongRange]

a little up date...i took my redding body die to the smith and had him take .020 off the bottom on tuesday...i got home tuesday night and sized a case with a light cam over and the case was .001 longer...i took it back and had him take another .015 off yesterday and sized a case when i got home and with the die just touching the shell holder it bumps the shoulder just right for a nice snug fit...from 1.674 to 1.673-1.6735...i also tried sizing a couple of the first 100 cases and it leaves a ridge(for sake of a better word)just above the head so im going to toss those as im not comfortable shooting them again.

ive got 48 rounds loaded up to shoot today...if its not snowing by the time the sun comes up...ive got 24 rounds from 43.5g up to 46g of H4350 and 24 rounds from 42.5g up to 45g of RL-17 all with 142gSMKs .025 off the lands and CCI BR-2s in .5g increments...i have 4 rounds of each charge loaded so i will shoot at 6 separate targets with each powder for a total of 12 targets...1 round from each charge weight will be shot over the magneto speed starting low and going up...if and when i hit 3000fps i will stop there and then shoot the other 3 rounds at the same target as with the magneto speed but i will shoot 3 round groups not a round robin.

im not sure if im going to try the RL-19 or not until after i shoot the H4350 and RL-17...i guess if these dont shoot i will but im hoping to find something with these two tests as im not a fan of RL-19...its accurate but very dirty powder...then again dirty might be good in this barrel LOL.

so far ive had 3 of the winchester cases that have loose primer pockets and im guessing they were the ones i had the 139g lapuas jammed in the lands last weekend...so far im pretty impressed with the win brass especially at half the price of the lapua...if it holds up today i might just buy another 500pcs.

[upSLIDEdown]

Just load up some RL17 and get on with it!! All this chitterchattering is wasting valuable time! Haha

.

lolol

[Oxn316]

I ran winchester brand 243 cases in my standard 260 and I was getting 13-14 reloads on them. If your loads are not too stout they will last.

[LongRange]

.

lolol

i missed that one LOL...the RL-17 is loaded and ready as well as the H4350...im hopping to get out today.


I ran winchester brand 243 cases in my standard 260 and I was getting 13-14 reloads on them. If your loads are not too stout they will last.

good to know...im pretty impressed with the consistency of the win brass as far as the internal capacities go but not so much with the rest of it but at $26 bucks per 50 and since i prep all of my brass anyway i am perfectly happy with it...i will admit im an over loader so we will see how it holds up.

[LongRange]

i did get out yeserday afternoon and fire formed 49 more pieces of brass...one piece outta the bag had a V shaped piece missing out of the neck...i used some old 140g nosler custom comps i had and i dropped the charge to 46g of H4831sc and they formed nicely.

http://i1239.photobucket.com/albums/ff515/LTT-/Mobile%20Uploads/1451044631.jpg (http://s1239.photobucket.com/user/LTT-/media/Mobile%20Uploads/1451044631.jpg.html)

when i got home i cleaned the barrel and it had A LOT of copper in it...the patches looked almost black there was so much copper....i had to short stroke the throat with patches and had to run a bronze brush through the barrel several times to get all the copper out...that was the worst copper ive seen since my factory 300wm barrel...im not sure if it was from the custom comps or from the brass being a little off in the chamber when fire forming...ive noticed that several of the primer strikes are off center a little when fire forming but either way ill have to keep a close eye on this fouling.

if the wind isnt blowing 25mph today ill get out and shoot the test rounds i have loaded...yesterday when i FF'd those 49 pieces the wind was howling and it was cold...2 20 shot groups and a 9 shot groups and i was numb LOL!

[LongRange]

ok this little AI project has my full attention after shooting this morning...still cold as he!! and 15 or so MPH wind...i shot just as i said above...1 round over the chrony from each powder and from each charge weight...i shot the H4350 first...

H4350...round #1 43.5g 2789...round #6 46g 2917...disappointed i did shoot the other 3 rounds of the 46g load after i shot the 6 rounds of RL-17 over the chrony...

http://i1239.photobucket.com/albums/ff515/LTT-/Mobile%20Uploads/1451068706.jpg (http://s1239.photobucket.com/user/LTT-/media/Mobile%20Uploads/1451068706.jpg.html)

next the RL-17...round #1 42.5g 2799...round #6 45g 2951...at this point im back interested in this...so i pulled the magneto speed off and shot the 46g H4350 load then shot the 45g RL-17 load not expecting this....the one hole just to the left was the round i fired over the magneto speed the other 3(i know its just a 3 round group)i shot without the magneto speed....

http://i1239.photobucket.com/albums/ff515/LTT-/Mobile%20Uploads/1451068886.jpg (http://s1239.photobucket.com/user/LTT-/media/Mobile%20Uploads/1451068886.jpg.html)

i shot the next lowest charge of RL-17...44.5g 2932...but it opened up a bit so i packed up and came home without shooting another round...im going to pull the rest of the rounds apart i had loaded,size the necks and load them back up with RL-17 and run it up to 46g...i think im going to load a few with RL-19 as well just to make sure im not missing out on something LOL!

im done with the H4350...at 46g it was starting to flatten primers and had quite a bit more felt recoil....the RL-17 had much less felt recoil and the primers still have nice round edges...at this point im real curious to see how this load holds up and if it gets better...also curious to see how the RL-19 preforms...ive had great luck with both these powders but like ive said the RL-19 is very dirty but may clean up if ran higher than i have in the past.

also after shooting the powders and primers i have i am having a hard time believing some of the claimed velocities ive read on other forms(i know its the inter net where everyone is someone LOL)...i read somewhere(reloaders nest i believe)a guy saying he was getting 3050 or 3075FPS with a 140g bullet and 45g RL-17...all i know is that i just shot from 42.5g to 45g of RL-17 with a 142g SMK and a CCI BR-2 in .5g increments and the average gain was about 30FPS and with the H4350 it was about 20FPS for each .5g increase...100-125FPS faster with the same charge weight is not impossible i guess...just hard to believe.