We are starting load development, 7MMx57 AI.

[D4570]

I'm still fire-forming the AI part, but we have enough brass to start loads.
I want to keep them around 2700, or 2800 fps Similar to the factory 7x57 in a 140-ish bullet.
It's for a small framed 14-year-old girl. She has been shooting for 8 years and is very good. But does not enjoy heavy recoil, is not afraid of it but does not like it.
She is shooting a Ruger American re-barreled with a Shaw barrel 1x7 twist, 22".
This is the first try.
She is shooting off a bench with sandbags at 100 yards.

LRX 145 gr best of 3 loads.
The recoil with Big Game Powder has noticeably more recoil.

ttsx 140 gr best of 3 loads.
Check out the fire-forming target 20 shots in an inch and a half.

 

[D4570]

 

[D4570]

Sorry I cant get the other pics to open after I post it

 

[std7mag]

I built my daughter's Mauser in straight 7X57 Mauser.
Rifle is a little on the heavy side, but helps mitigate some recoil for her.
The Boyds AT-One stock really helps with fitment!

I'm loading up 120gr Nosler Ballistic Tips with lower accuracy node of RL17.
Perform well on PA white tailed deer.

 

[ImBillT]

I would really like a 7x57AI in a Mauser action, but for the purpose at hand, why a 7x57? Why the AI? Why a 7” twist? Heck why not 6.5CM? Would have been easier on everyone, especially the girl.

 

[D4570]

She wanted a step up from her Howa mini action 6.5 Grendel.
We acquired 200 factory ammo so we had the brass.
I had a new Ruger American in '06 that I did not need.
We were looking for something nonmainstream.
Her uncle has a 7mm08 She shot and liked it.
Her mom has a 6.5 Creedmoor and thinks it is an okay round.
7mm rem mag is just too much.
So that's how we came up with a 7x57.
The AI Is, we're getting a barrel so why not?
Like a 3 1/2" shotgun you don't have to shoot 3.5 but you can if you want.
AS she gets bigger we can up the load and bullet weight if she wants.
The AI advantage is also, the cases don't stretch as badly so there is seldom any trimming needed. The 7 twist is for longer bullets if ever needed.
There, that's how it started.
By the way, the 7mmx57 seems to recoil about the same as her mom's 6.5.

 

[ImBillT]

She wanted a step up from her Howa mini action 6.5 Grendel.
We acquired 200 factory ammo so we had the brass.
I had a new Ruger American in '06 that I did not need.
We were looking for something nonmainstream.
Her uncle has a 7mm08 She shot and liked it.
Her mom has a 6.5 Creedmoor and thinks it is an okay round.
7mm rem mag is just too much.
So that's how we came up with a 7x57.
The AI Is, we're getting a barrel so why not?
Like a 3 1/2" shotgun you don't have to shoot 3.5 but you can if you want.
AS she gets bigger we can up the load and bullet weight if she wants.
The AI advantage is also, the cases don't stretch as badly so there is seldom any trimming needed. The 7 twist is for longer bullets if ever needed.
There, that's how it started.
By the way, the 7mmx57 seems to recoil about the same as her mom's 6.5.

All good reasons!

While for most people I would advise the 6.5CM, I think the 7x57AI is better if there’s an intention to load heavier than 140gr.

While I don’t like using more twist than necessary, a 7” might be necessary if you intend to go heavy with solid copper.

 

[EastTNHunter]

That velocity window with that weight bullet is great for deer or antelope. This was a 130gr .270 Win at about 2800 or 2850. Dropped it in its tracks

 

[Salmonchaser]

Well I’ve covered just about every caliber group from 577 NE to 223s. I’ve had a 7x57 for about 4 or five years now and absolutely love it. Lots of versatility and plenty of horse power for reasonable ranges. If my grand daughter wants to go elk hunting she’ll use it. Looking forward to your reports. I’ve had good luck with Rl 17 and 26 getting 140s over 2900 fps. H4350 has been very accurate in the 2750 to 2800 range.

 

[D4570]

I have RL 26 and use it in a LOT of Big brass rounds, 8mm,375 ext.
Great speed accuracy and no were near the recoil as many other powders.
Can you PM me as to a starting point on your 57?

 

[std7mag]

Yeah, RL26 is a pretty versatile slow powder.
But it's not necessarily the best powder for all cartridges.

With the case volume of the 7X57AI, I'd look at something more in line with RL19 or IMR4831 burn speeds.
Vihtavouri N555 would do well also, and is fairly available for a decent price.

All 3 of those do well in the 7X57 & my 257 Roberts AI.

 

[D4570]

We have RL 15, 17, 19, and 26. We have H4350 and it looks like it has some good promise too.

 

[Justabirdwatcher]

She wanted a step up from her Howa mini action 6.5 Grendel.
We acquired 200 factory ammo so we had the brass.
I had a new Ruger American in '06 that I did not need.
We were looking for something nonmainstream.
Her uncle has a 7mm08 She shot and liked it.
Her mom has a 6.5 Creedmoor and thinks it is an okay round.
7mm rem mag is just too much.
So that's how we came up with a 7x57.
The AI Is, we're getting a barrel so why not?
Like a 3 1/2" shotgun you don't have to shoot 3.5 but you can if you want.
AS she gets bigger we can up the load and bullet weight if she wants.
The AI advantage is also, the cases don't stretch as badly so there is seldom any trimming needed. The 7 twist is for longer bullets if ever needed.
There, that's how it started.
By the way, the 7mmx57 seems to recoil about the same as her mom's 6.5.

I think you made some good choices. I've always heard that for AI's 7x57 or 7mm-08, to use the max published load as your starting load, but I've never had an AI's round either. I think of all the AI's, the 7x57 makes the most sense. As you say, she can grow with it. Should be a fun one to load for.