260 AI loading questions

[atl5029]

Hi guys,

I know this is technically in the wrong sub-forum, but I had this post on the reloading section for several days with no help. But since we often talk about bullets and loads here too, hopefully some of you can shed some light.

My 260 AI rifle is very near completion, and I have some questions about hand loading for this round and fire-forming brass.

1. My first question is, can I use my 260 AI dies to hand load standard 260 Rem loads for fire-forming? Will the FL resize die properly size the necks and will the seater die properly seat the bullets in standard 260 Rem cases? Or do I need to buy standard 260 dies as well?

2. For my first batch of brass, I intend on just shooting bullets to fire-form instead of using a cream of wheat method or something similar so I can get my rifle near-zeroed and get some practice in. I've read that to keep the cartridge head against the bolt face and avoid stretching of critical parts of the case during fire-forming, that you should seat the bullets to touch the lands of the rifling so that the case can not move forward. My chamber has a longer throat, but I'll be using 140 gr Amax bullets, which should have plenty of length to touch the lands. Anyone see anything wrong with this?

3. When loading fire-forming loads for AI rounds, I've also read you can start near or at the max load of the standard round for a good starting point for the AI round. When loading standard 260 to fire-form, can I start at the max load or should I still work up from a minimum load?

4. If anyone would like to share good loads for the 260 AI I'm all ears. My hunting load will be running the 140 grain CEB MTH. I also have 140 grain AMAX bullets and have some 140 grain ELD-match bullets on backorder. Right now I have IMR 4831, 4064, Varget, and some surplus powder similar to 4895 on hand. I've read Reloader 17,19, and 22 work well for this round, as well as Superformance. What about fire-forming loads? Would a recipe with a slower velocity at max load be better for barrel life?

Thanks!

 

[Plade]

Hello I see no one has replied to your 260AI questions so here goes.

I shoot a 260AI with 26" barrel here in New Zealand. Primarily I use it for hunting but also some steel target just for practice. I have used both cream of wheat and fire forming live rounds to form brass from a standard 260 case. In both situations you will need to form a false shoulder on the case so that the case is held firmly when you close the bolt. If you don't then you will suffer misfires as the case can be pushed forward slightly by the firing pin impact. It should be a firm bolt closure and you will then have the case locked in the chamber and ready for forming.

Although its messy I prefer the cream of wheat method. I do not run full power loads if fire forming as these are near max pressure and I do not deem it prudent. I prefer to go into the field with a case that is formed and ready to shoot the load I want. You will find fire forming loads are accurate - you will just have a different point of impact.

I have spent some time developing accurate long range hunting loads for this caliber. I always shoot 140 gn bullets either Amax or VLD. I anneal all my VLD's for better long range performance on game. Vhitavouri n560 is my powder of choice as it has lower peak pressure whilst providing the velocity I am looking for. I am using 50.1gn with a long COAL of 78.5mm with the VLD's. This gives me 2950 fps with very low ES and about 8 reloads per case.

Hope that's useful

 

[Santiam338]

Good luck with your 260ai..I have had mine less than a year now and really like this chambering.

I am shooting 140 Bergers with IMR4831..I had planed on H4831 but none was available..Tried the IMR version and was completely satisfied with the results..

47.3 gr is getting me 2970 and great accuracy..I don't really see how I can improve with this load so have quit looking.. I am up against the max so work up of course.


As for fireforming , I shoot 120 A-maxes with a medium load of reloader 17. I do use my ai dies to reload with no problems. I am using Lapua brass and can't seem to wear it out..It makes fireforming kind of a non issue..You don't have to do it much..LOL

My first score with the 260ai..

 

[PGJPJ]

very cool guys! I just finished a 280ai build. If I was building a short action, I would have looked hard at the 260ai.

It's kind of that magic combination. Not a lightning rod, barrel burner, but has enough horse power to push the heavier high BC 6.5 bullets.

Just a sweet package.

 

[codyadams]

Hey Santiam338, mind me asking what your barrel length, rifling, and twist rate is? I'm having a barrel made by krieger, Gonna be a .260AI on a rem action, a medium palma 4 groove 1 in 8, going to have finished length be either 28 or 30", haven't decided yet. My goal is 3,000 w/140's, and I have H4831SC and can get Alliant reloader powders if needed. Already have lapua .260 brass. Going to try the Berger 140 and Hornady's new 143 ELD-X.

 

[Santiam338]

It's a Shilen select match,26 inch 8 twist.. ..3000 fps was pushing it much to hard from what I could see..

Good luck

 

[Plade]

Cody, in my experience you will not get the 3000 fps velocity with H4831SC before running into pressure problems. I have some data on using one of the Alliant powders but found them only really suitable for shooting lighter projectiles in this caliber. From memory they worked fine with the 123gn amax but nothing heavier. Vhitavouri N560 is the clear winner with the 140gn weight bullets.

 

[Plade]

I had an enquiry on loads for the 260ai from another LRH member earlier this year and I gave him a more comprehensive reply on my experiences with the 260AI as follows:

Hello Nick, yes I have considerable experience with the 260AI. It is a great round and a big improvement on the std 260. I shoot using an accurised Howa short action with a 26 inch barrel, suppressor and jewel trigger set at 1.5 pounds. I had my barrel cut with a relatively long throat so I can seat the 140 gn projectiles out as far as practicable.

My goal with this rifle was always to be able to shoot a 140gn 6.5 projectile at 2950 fps MV accurately. I have tried a heap of bullets and powders. Needless to say you are pushing pressure, barrel and case life when you get to 3000 fps but it is achievable even out of a 26 inch tube.

I won't draw up a list of powders and results but here is a summary:
h4831sc - good accurate powder but limited by pressure and not quite the velocity. The max I went to was 50.5gn for 2921 with the 140 gn VLD hunting and 2943 with the AMax. Group size had expanded at max pressures to 1.231 moa. Results with 49.8 gave an ave of 2885 fps and .8 moa.

I have tried H1000 but even using a drop tube I could not get enough powder in the case to give a suitable velocity.

I have tried a variety of others but the one I use now and recommend is vhitavouri N560. I have now settled on 50.1 gn using a BR2 primer, rem 260 formed cases and 140 gn VLD hunting bullet. I am putting these out at 2950 fps with low es and extremely low pressure. I am getting 8+ reloads per case with very good accuracy (better than .7 moa). Max load in my rifle is 51.9 gn for 3050 fps however primers will fall out of cases after two or three firings.

Aside from the occasional session at a steel plate just along from where I live, all my shooting is for game and usually at ranges out to 800 yds. I limit myself to this distance as this caliber really starts to lack energy beyond this. To help things along I anneal my 140 VLD's so that they fragment better at slower speeds. Here in NZ we have a lot of opportunity for hunting and its all year round. Consequently we get a lot of experience shooting animals. I have harvested goats out to 840 yds and red and fallow deer out to 700 yds.

This is a great 6.5 caliber and you will not be disappointed.

I also had the chance to check my data and it was Aliant RE 19 at 49.5gn with the 123 Amax to give an accurate 3108 fps.

Hope that's useful to all you 260AI shooters