22-250AI fire forming loads

[TZaun]

Getting ready to start loading for my latest project. It has a 28", 1:7.7" twist and I have 77 gr. Lapua Scenar-L and 80 gr. Sierra Matchkings to try in Lapua brass. I've read a lot of guys like the 4350s in this weight range. I'm looking for a good charge weight to start with and any other powders and their respective charge weights for fire forming bullets in this range. To be clear, I'm going to work up a load that shoots great while fire forming, I just need a safe place to start. I won't do a seating depth test as I plan to fire form all rounds jammed .020". Thanks guys.

 

[bheadboy]

take Hodgdon max load for 22-250, reduce by 1 grain and shoot. I have done this with 4 different AI calibers and it worked on all as a starting point to then ladder.

with your plan on Jam of .020, you may want to reduce 1.5 grain for first shots. worked for me , may not for you.
h414 and the 4350's should do

Bob

 

[TZaun]

Thanks. That's good to know. From what I've read on fire forming, jamming .020" will help give you straighter cases and a better form, correct? Or is that not necessarily the case?

 

[bheadboy]

in my experience, jamming does a couple of thing, it gets the bullet seated in the lands, increases pressure, and to some applications give good accuracy, it can also cause erratic performance if loads are not properly adjusted for the additional pressure

problem is the case unfireformed is not filling the chamber and the jam may cause the case to shift - a touch or modest jump of .010 allows the case to expand as the bullet moves into the lands and pressure builds, just my opinion


Bob

 

[CatShooter]

in my experience, jamming does a couple of thing, it gets the bullet seated in the lands, increases pressure, and to some applications give good accuracy, it can also cause erratic performance if loads are not properly adjusted for the additional pressure

problem is the case unfireformed is not filling the chamber and the jam may cause the case to shift - a touch or modest jump of .010 allows the case to expand as the bullet moves into the lands and pressure builds, just my opinion


Bob

If the case is not held against the bolt face for the first shot, then it will stretch and is on the way to a head separation that can not be reversed. It is a BIG problem with Ackleys that do not have enough crush

.

 

[bheadboy]

Catshooter has a point, often heard, and may well be true, I have just not experienced it

in my experience, using the touch or.010 jump with the load near max, has worked, I have had over 10 reloads in 2 280 ai's and 6 so far with 7-08 AI with 260ai had 5-6 then sold the gun,

none separated or showed signs of doing so.

this could be a border line event some get and other do not

Bob

 

[Geno C]

You need the right headspace. Then a bit of a jam is best. Otherwise this can happen

 

[vlcakc]

"Crush fit" is not the same as "jam". AI's must be chambered shorter than the parent cartridge to prevent case separations. The usual recommendation for the 22/250AI is -0.004" shorter than a standard 22/250 Rem. This is usually accomplished during chambering by using the standard 22/250 Rem "go gage" as the "no go" gage and using a 22/250AI "go gage". Actually I prefer a even slightly shorter chamber than -0.004" to ensure a tight crush fit on new cases. When the proper chamber length is used, jamming the bullets is not required at all. I use near max standard 22/250 Rem loads for fire forming. Vic

 

[Geno C]

I know the difference between a crush fit and a jam. I was relating that a jam has worked best for me. A crush fit is necessary so you don't end up with the separations I pictured. Sorry for the confusion

 

[CatShooter]

"Crush fit" is not the same as "jam". AI's must be chambered shorter than the parent cartridge to prevent case separations. The usual recommendation for the 22/250AI is -0.004" shorter than a standard 22/250 Rem. This is usually accomplished during chambering by using the standard 22/250 Rem "go gage" as the "no go" gage and using a 22/250AI "go gage". Actually I prefer a even slightly shorter chamber than -0.004" to ensure a tight crush fit on new cases. When the proper chamber length is used, jamming the bullets is not required at all. I use near max standard 22/250 Rem loads for fire forming. Vic

0.004" of crush is not adequate - that is where the head separations come from.

When Nosler tried to get the 280 AI standardized and accepted by SAAMI, SAAMI kicked it back with a "Bad Engineering practice" remark... they required a minimum of 20 thou of crush.

Most gunsmiths are too cheap to get a set of AI gauges - they just use the no-go as a go, and grab the money and run.

 

[TZaun]

Thanks for the great info guys. When you say .020" crush fit, it must be really hard to close the bolt then, correct? Or am I thinking about this wrong?

 

[Ackman]

The 22-250 case has a lot of taper. Forming to AI blows it out quite a bit. Fireforming with an under max load for the std case is ridiculous. Finding an accurate fireform load, start at max for the std. 22-250 and go up from there. Fireforming will be nicely faster than a max std. load, accuracy will be as good as with formed brass.

A properly cut chamber holds the std. case just fine. No need for seating into the lands.

Thanks for the great info guys. When you say .020" crush fit, it must be really hard to close the bolt then, correct? Or am I thinking about this wrong?

The case is only being contacted at one spot, the neck / shoulder junction. And it doesn't take a tremendous amount of force to move that radius back. With .020" crush you feel pressure but it's not hard to close the bolt. My 22-250AI's all have been set with .025" crush. The bolt doesn't need to be muscled. And regardless of what some might say, galling isn't a factor.....really.

 

[CatShooter]

The case is only being contacted at one spot, the neck / shoulder junction. And it doesn't take a tremendous amount of force to move that radius back. With .020" crush you feel pressure but it's not hard to close the bolt. My 22-250AI's all have been set with .025" crush. The bolt doesn't need to be muscled. And regardless of what some might say, galling isn't a factor.....really.

Yup.... what he said!

 

[TZaun]

That's really good info. Thanks a bunch!!

 

[A_Gamehog]

Some good info for you.

http://accurateshooter.net/Blog/sierra22-250ailoads.pdf

 

[TZaun]

When you turn your necks before fire forming, do you turn all the way to the shoulder? I appears to me that the neck length stays the same?

 

[JAnderson94]

I only have a 9 twist, so I fire form with a 53 VMax. I have been using CFE223 1/2 grain over max for a standard 22-250 with wet moly'd bullets. (3900fps fire forming) I have used this to blow out Lapua cases 100% the first firing. Its on a Savage action so I did set up very very minimum head-spacing. There is slightly less effort to cycle the bolt then a neck sized case that needs shoulders bumped back.

I would not start below a max 22-250 load for fire forming, none of my bullets are seated into the land either. After fire forming they chamber like butter, no effort on bolt close/open.

 

[daniel brothers]

some good information here Guys...

 

[TZaun]

I took 3 brand new .22-250 Lapua brass out of the box and checked runout. .003", .005", & .006" runout on those 3. I then turned the necks to .0125" right up to the neck shoulder junction. I loaded up 77 gr. Lapua Scenar L into the lands .020", on top of IMR4350, and a Fed. 210 primer and shot them. Everything looks really good. The neck turn was perfect as the necks did stay the same length after the fire form. The runout after fire forming was .001", .001", and a little less than .002". Now to get them on paper and see how they shoot.