260AI starting load

[codyadams]

I'm having a 260AI built, and I have 100 rounds of LAPUA .260 rem brass waiting for a gun. I figure I will use a box of hornady 140gr bthp bullets to fireform and break the barrel in, but I have never fireformed for an AI, and just wanna make sure I'm not missing anything. So this is my fireform/break in load

46.5 gr H4831 SC
LAPUA .260 rem brass
CCI LR primer
Bullet seated to touch lands

Sound about right?

Thanks in advance for any replies. Stay safe, and God Bless America.

 

[MudRunner2005]

Congrats on the .260 AI. You should enjoy it. I have been wanting to build one for quite a while now.

Everything sounds good, except I wouldn't use a full load for fire-forming with a bullet seated into the lands. That's asking for some serious pressure spikes. I have 3 Ackleys and I use a reduced load (about 75% charge) to fire-form for all of them, that way it doesn't overpressure and crack the necks and blow out the shoulders when that case is forming to the Ackley chamber.

Just my $0.02...

 

[FEENIX]

I'm having a 260AI built, and I have 100 rounds of LAPUA .260 rem brass waiting for a gun. I figure I will use a box of hornady 140gr bthp bullets to fireform and break the barrel in, but I have never fireformed for an AI, and just wanna make sure I'm not missing anything. So this is my fireform/break in load

46.5 gr H4831 SC
LAPUA .260 rem brass
CCI LR primer
Bullet seated to touch lands

Sound about right?

Thanks in advance for any replies. Stay safe, and God Bless America.

I do load development for both non-fireformed (non-AI, perfect for barrel break-in period, no reduced load or cream of wheat method for me ... ~150 fired without any problems using WW brass) and fireformed (AI) brass for my .270 AI, this way I'll have accuracy load for both.

Good luck!

 

[TOM H]

I'm having a 260AI built, and I have 100 rounds of LAPUA .260 rem brass waiting for a gun. I figure I will use a box of hornady 140gr bthp bullets to fireform and break the barrel in, but I have never fireformed for an AI, and just wanna make sure I'm not missing anything. So this is my fireform/break in load

46.5 gr H4831 SC
LAPUA .260 rem brass
CCI LR primer
Bullet seated to touch lands

Sound about right?

Thanks in advance for any replies. Stay safe, and God Bless America.

With the AI you can chamber rd so don't need bullet against the lands and case form after one firing. What ever powder I'm going to use for AI that's what I going to use on breaking barrel and do little load development blowing the cases out.

If you could get 10/15 cases formed first time that give you enough to start for the AI and still do some case forming. I do agree with Feenix about having loading data for both.

I've done it lot different ways over the years and you may find something after you start that works better. Well good luck

 

[MTGunner]

load 46.0 gr. of H4350 for my 120BT. The fireform and bbl. break in loads were 1 gr. less for my 260AI. I have loaded 130VLD Bergers with great performance, albeit the 120BT has accounted for many, many big game animals. You will be impressed with your 260AI. Good luck! MTG