257 Roberts AI

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Muskydawg

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Hi guys, kind of inspired to have a .257 Robert’s AI. Starting to realize that to have one you basically have to build it. So that got the wheels turning. Now I’m thinking about doing my first rifle build.

I’m thinking about a “modern” .257.

But I’m starting from scratch… so, I’m coming to you guys. Again, I’ve never built a rifle, so spare me if these are stupid questions!

Could I start with a Tikka T3 or T3x action? Would I have to have a barrel cut? Or would someone sell a pre made .257 AI barrel? Maybe a proof research carbon barrel on a tikka T3x?

I have a savage backcountry 280 AI with a proof barrel and like it.

I have a Sako carbon lite 300 win and really like the feel of the stock. Maybe there is an aftermarket stock for the tikka that is similar?

Just putting some thoughts out there, looking for some feedback.

Thanks for any help!
 
257 Bob AI is a great cartridge. I am unaware of any prechambered barrels for it, so you'll need a 25 cal barrel and someone with the proper reamer to cut it for you. Your Tikka will work fine, with the added plus of being able to use their long action to allow you to seat your bullets out further. - dan
 
With enough money you can approach it any of the ways you asked about. You can rechamber a .257 or go full custom. It's a cartridge that hits way above its weight, good choice.
 
So get the dies and brass and the bullets you want to use... load a dummy round to the length you want... and supply that information to the reamer maker...and buy a Manson reamer made with the throat you want...

Make sure the action you use is long enough in the magazine... build away... it's not going to be cheap but you should enjoy it...
 
Is a Manson reamer different than a typical reamer? Or is Manson a brand? Is there a reputable reamer maker that I should send the dummy round to?

Also, an recommendations in barrel blank manufacturers would be appreciated.

Thanks!
 
Muskydawg said:
Is a Manson reamer different than a typical reamer? Or is Manson a brand? Is there a reputable reamer maker that I should send the dummy round to?

Also, an recommendations in barrel blank manufacturers would be appreciated.

Thanks!
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Manson is a brand, and a good one. PT&G sells reamers as well, and others. A web search will edify you greatly in that regard. Barrels? Well, again, do a web search for who makes 25 cal barrels first, and decide which twist you need, which will narrow it down. Then decide stainless or carbon steel, which will narrow it down further. - dan
 
Thanks for the info guys, I searched up Manson reamers right after I posted that last message (probably should have done that first!), looks like they have a 257 AI in their catalog, might just get a standard dimension reamer and load to suit it. Rather than send them a mock round. I’m excited, I think this will be fun. I like diving into new rabbit holes, it’s good for my OCD!!!

Once I get some components together I’ll update on how it’s going.
 
guntech said:
So get the dies and brass and the bullets you want to use... load a dummy round to the length you want... and supply that information to the reamer maker...and buy a Manson reamer made with the throat you want...

Make sure the action you use is long enough in the magazine... build away... it's not going to be cheap but you should enjoy it...
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This is really good advice. One thing to add though is that it's possible to get the reamer manufacturer to make up a set of dies for that reamer at the same time, which doesn't require that you send them a round. Just specify that you want them to match.

I did that with a 308 Palma Match reamer and die set, made by Clymer. I don't know if Clymer made the dies or not, just that they came 308 Palma Match stamped on the top, in a clear box, along with a shell head holder.

The rifle I made up on this setup was one of the most accurate rifles I've used and is now doing yeoman's duty in Southern Alberta.

I still have the reamer but the die set went with the rifle.
 
Muskydawg said:
Thanks for the info guys, I searched up Manson reamers right after I posted that last message (probably should have done that first!), looks like they have a 257 AI in their catalog, might just get a standard dimension reamer and load to suit it. Rather than send them a mock round. I’m excited, I think this will be fun. I like diving into new rabbit holes, it’s good for my OCD!!!

Once I get some components together I’ll update on how it’s going.
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One thing about the 257AI, over its original 257Rob, once you reach a point near maximum pressures build up quickly.

The 257AI was one of the few cartridges I managed to get loose primers after the first shot.

The powder I used back then was H4831. With some of the more recent powders available, such as IMR7828ssc it may not be much of an issue.

One other thing, concerning cases. You're going to have to fireform 257Rob cases and there are two quite different types of cases made for this cartridge. If the box or bag isn't labled +P and the headstamp doesn't include +P then you need to take care, because the side walls and web are thinner and not able to be loaded to the pressures the 257AI is capable of generating.

I finally just decided to stick with the original 257Rob chambering in a Remington 700. I exclusively hand load +P cases for it, made by Remington.

I use a load of H414sl10, which is one of the early experimental non temperature sensetive versions of H414/W760, over CCI 250 primers, under 100 grain bullets.

My magnetospeed tells me this load generates 3000+fps out of my Rem 700 with a 23.5in bbl.

This cartridge really does well with slower powders. If you go online and check out HOT 257Rob loads, you will find some very impressive starting points for various weight bullets and intended to be used only in modern, strong actions.

Many of the early 257Rob rifles were built on action not quite as sturdy and the information listed in most loading manuals reflects this. Some manuals will give loads appropriate for modern actions but usually have a printed ''caution'' statement to go along with them, while still being on the cautious side.
 
That’s great info, I was reading about the +p last night, trying to figure out the difference. I’ll watch for the +p brass.

So another question, that might be obvious, but I’m new! Are the bolts in all long actions the same? I talked to the tikka rep this morning, and stoeger won’t sell any actions or parts separately. So if I find any long action tikka to start with will it work? I’m going to look for a new gun to use as a donor action. I don’t want to disassemble any of the tikkas I already have.

Also, is a Tikka action a good one to use? I’ve always been happy with them, but is there something I don’t know?

Thanks for all the feedback.
 
Muskydawg said:
That’s great info, I was reading about the +p last night, trying to figure out the difference. I’ll watch for the +p brass.

So another question, that might be obvious, but I’m new! Are the bolts in all long actions the same? I talked to the tikka rep this morning, and stoeger won’t sell any actions or parts separately. So if I find any long action tikka to start with will it work? I’m going to look for a new gun to use as a donor action. I don’t want to disassemble any of the tikkas I already have.

Also, is a Tikka action a good one to use? I’ve always been happy with them, but is there something I don’t know?

Thanks for all the feedback.
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To my knowledge, the Tikka T3 actions are the same length but their bolt faces will be differerent, depending on which cartridge they're chambered for and the magazines will have spacers in them to coincide with the cartridge length. The bolt stops will be the appropriate length for the length of retraction required for that cartridge.

Muskydawg, my advice to you is don't #### around with this particular build.

Nothing wrong with the cartridge but it's a very expensive rabbit hole you likely don't want to go down, for a hundred feet per second velocity increase.

The 257Rob, with the modern components available today will do everything the 257RobAI would do, back when it was first thought to be ###y to make such wild cats up.

If you're seriously looking for something in the 25 caliber diameter take a step up and go to the 25-06, which has readily available brass/dies and is considered by some to be in the magnum category.

This is a very real observation, based on a lot of experience.

There are some very good smiths out there that can very easily make up the rifle you are dreaming about. IT WON'T BE CHEAP, which is what I think you're trying to do.

Your money will go much further, purchasing a rifle, of good quality, off the shelf, chambered for a cartridge the meets your requirements.

Unless you can do all of the work required to do this job yourself and you have a limited budget, this project will quitel likely join thousands of similar projects languishing in the shops of DIYs and collecting dust, until reality sinks in and the project components get dumped to recoup some of the costs appx 10-20 years later.
 
Thanks guys, a lot of great points! I talked to the tech desk at Manson today (very helpful, I think his name was Rick?), they have standard size 257AI Reamers. I think I might just go with that, instead of getting a custom reamer made. I don’t have any brass yet, and I don’t have a rifle, so I can’t fire form any brass. If anything, down the road, it sounds like I could get a throat cutter (probably not the right term) and punch it out a little more if I want to run a longer bullet. But I think standard sizing and standard dies will be a good starting point.

Is the tikka action a good one to build off? I like the action in their factory setups, but I’ve never heard of someone building a custom gun off of one? Is their any red flags I should know about? As far as I know, tikka only makes 2 actions correct? Short and long? I think a 257AI is best based off a long action right?

Thanks for all your help! I live in a small rural town, lots of gun guys here, but I don’t know anyone that likes to get this “deep into the weeds”!
 
If you're talking about the Tikka T3, the actions, to my knowledge, are all the same length and only the bolt faces are different, depending on the cartridge they're chambered for.

You're going to have to find a smith that's experienced with these actions to make sure you get a decent build done.

Tikka doesn't chamber their rifles in 257Rob, so it will have to be rebarreled. However, they do chamber their rifles for the 25-06 and guarantee 1moa or less accuracy.

Winchester/Remington/Weatherby/Howa and several other manufacturers chamber their rifles for the 257Rob and can be easily reamed out the the standar 257AI.

The 257AI is a pretty standard conversion, and many smiths already have the reamers on hand, which makes the job much cheaper as they will only be charging you for it's use instead of retail price for a new reamer.

Modern 257Rob rifles usually have quite long throats, unlike the earlier variants. Modern rifles will also have tighter twist, to accomodate heavy for length bullets, all the way up to 125 grain ELDs.

I haven't seen a 257AI reamer that didn't have long throat.

It's next to impossible to purchase a Tikka receiver, unless it's one that has been stripped from a complete rifle.

A used Tikka, depending on whether its blued or stainless will cost you at least $750 and you have to be sure of the bolt face.

Magazines are available but even used, start at $75+

This build, if your donor rifle comes with a stock you like, isn't going to be cheap.

$1500+ minimum, without any add ons, such as scope, triggers, metal trigger guards, extended magazines etc. This would be a minimal price. Then add on specialty dies and the list goes on.
 
Thank you for your concern and honesty bear hunter. I’m not considering this build to save money, I’m considering it for the sake of having a unique rifle that nobody else has! Honestly, I was expecting it to cost about $4000.

Your last message spurred another question for me though. Reaming out a 257 Rob? If the AI has a steeper shoulder on it, would the reamer not have to go in further to cut that shoulder? Would that not in turn affect the headspace, making it to long? I’m definitely not questioning your knowledge, just trying to understand how it all works!

Thanks for your input
 
There is nothing unique about the better Bob, many boobs have built one. You would be further ahead to build or buy a 257 Weatherby and do some killing with it. If somewhere down the line you still yearn for sub par performance in a 25 cal rifle, it can be had with the starting loads for the Weatherby in any manual.
 
In order to re-chamber a 257 Roberts to 257AI, the barrel has to be set back one turn in order to wind up with proper headspace. A 257 AI, built on a Tikka action, would indeed be somewhat unique. You would be able to get good performance from a small case. Of course, you could always buy a 257 Weatherby. This would allow you to strut about, with your chest puffed up, and proclaim to the world that you have a Weatherby magnum!
Ron Smith can provide a barrel in any twist you like, including a gain twist, and I'm quite certain he has a 257AI reamer as well.
 
Haha Weatherby owners are so proud, it’s great. I just can’t get excited about them myself. Maybe I’m just not exquisite enough to understand!
 
Muskydawg said:
Thank you for your concern and honesty bear hunter. I’m not considering this build to save money, I’m considering it for the sake of having a unique rifle that nobody else has! Honestly, I was expecting it to cost about $4000.

Your last message spurred another question for me though. Reaming out a 257 Rob? If the AI has a steeper shoulder on it, would the reamer not have to go in further to cut that shoulder? Would that not in turn affect the headspace, making it to long? I’m definitely not questioning your knowledge, just trying to understand how it all works!

Thanks for your input
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They take a thread or so off the barrel (depending on whetherbthere are sights on it or not, and the amount removed will vary depending on the thread), then run the reamer in to cut the new chamber. - dan
 
Leeper said:
In order to re-chamber a 257 Roberts to 257AI, the barrel has to be set back one turn in order to wind up with proper headspace. A 257 AI, built on a Tikka action, would indeed be somewhat unique. You would be able to get good performance from a small case. Of course, you could always buy a 257 Weatherby. This would allow you to strut about, with your chest puffed up, and proclaim to the world that you have a Weatherby magnum!
Ron Smith can provide a barrel in any twist you like, including a gain twist, and I'm quite certain he has a 257AI reamer as well.
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All correct, and Ron makes some nice barrels, I own a few myself. Have never been disappointed. - dan
 
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