I currently am tuning up a .243win Encore for a pronghorn hunt in 2021. I've come to realize that there's only so much I can do with that rifle due to its 1:10 twist. I'm also anticipating needing to shoot from a bipod or tripod and the Encores are really sensitive to forend pressure.

Brings me to why this is posted in the Bolt Action section.

I have a long action Savage 110 in .300wm that I really enjoy and I'm pretty enamored with high-BC 6MM bullets right now. I'm considering going switch barrel on this Savage for economics reasons. Not trying to build a PRS rifle or anything. Would like feedback on two options below-

1. Stay with .243 because I already have tons of brass, and Forster dies. I would get a 7 or 8 twist Shilen prefit and I think I can get an honest 3000 FPS from the standard case. Should only cost me a barrel, bolt face, and internal mag body to swap. Pros to me are low cost to get started, super low recoil. Cons are possibly feeding challenges and barrel life.

2. Some other long action 6MM. I'd probably still get a 7 or 8 twist Shilen prefit, and would probably still need a bolt face (I don't think I'd entertain the 6MM magnums) and probably internal mag. Probably looking at a couple hundred dollars more to get started with a new caliber for reloading between dies and components.

Is there a non-wildcat 6MM long action that would provide a 200+ FPS advantage over the .243win without going to the magnums? I guess .243AI would split the difference as I would have to buy dies, but I have almost 1,000 pieces of .243 brass to play with.

I think the .240 Weatherby is what you're after. I don't know anything about Savages and how much of a bitch it is to replace the bolt/bolt head but it's a .473 bolt face.

Personally I'd keep the 300 Win Mag barrel on it. With a heavy bullet going slow-ish you're not going to ruin any chops with good shot placement. I shot mine last year with a 30-06 AI with 165 Accubonds at 3020 FPS, and the year before was a 280 AI with 140 TTSXs at 3265 FPS. The 30-06 one was at 415 yards and at that range you don't need a super high BC bullet.

How far are you planning on shooting?

ETA: With a 243 AI I can get over 3300 with a 105gr bullet using Reloder 26. I'm currently shooting them at 3280 because that's where they shot the best, but I worked up to 3325 or so IIRC. You can get more than 3000 from the standard 243 case using a slow enough powder.

Look for a donor savage to rebarrel. Mossberg too. The savage axis line takes standard savage barrels too.

Cabela’s/Bass Pro runs a Savage 12FV deal numerous times per year where a rifle costs $319. I plan to pick one up next time.

A switch barrel can work too given enough notice and time to rezero.

@Poop3rscoop3r

I do like my .300WM a whole lot. I've got it set up for 150 E-tips right now and that's what I shot my mule deer with last year. Granted that was an 80 yard shot and just about anything in my safe would have been sufficient.

I've shot 180 accubonds and interbonds out of this and they are just butt kickers out of a sporter rifle so I went light when prepping for my mulie trip to WY so I could shoot a 20-30 rounds in a range trip and still turn doorknobs the next day.

Bolt head swaps are pretty straightforward on the savages. They're about $35 too so I've actually already got a .473 bolt head on the way. Might not need it though if I can find a short action for a good deal. I might have a line on a .22-250 for a couple hundred bucks.

I want 400 yards on deer or lopes and obviously the wind in WY is my biggest challenge. I know getting enough energy to 400 isn't going to be an issue, just looking for a BC over .5 to make the wind less of a factor.

Just stick with 243. George Gardner can’t be wrong


https://www.6mmbr.com/243Win.html

I thought I had replied to this a long time ago.

I still think the 240 Weatherby is a great cartridge and I was seriously considering it when I built my last gun. I regret not doing it.

However you can push a 243 with heavy bullets over 3000 FPS. I know Reloder 26 is a good powder for it and I'm betting H1000 would work as well. That's the route I would go, and I would pick up that 22-250 if I was you instead of doing a switch barrel. While the idea of a switch barrel is great I'd rather spend a few hundred more and have 2 rifles.

I was in the same boat as you five years ago.  I have a 300WM Savage I put a high dollar prefit barrel on that I primarily used for elk hunting.  It sat dormant most of the year outside of that.  I ordered a 6.5-284 chambered barrel from X-Caliber.  It was so accurate and so much fun to shoot I ended up with a second Savage action and built another one from scratch and ordered 2 replacement barrels for each one.  Only way I am going to use the 300WM barrel again is to find another 110 action and build a 300WM on it which I will definitely do.  
Anyhow, if you are set on the 6mm/25 cal, maybe take a look at the 6mm-284 or even a 25-06.  I am completely sold on X-Caliber Barrels.  Have 7 of them now.  3 on rifles and 4 in boxes.  The three currently on rifles shoot dead nuts accurate.

Well lots has happened since my last reply here. First I settled hard on doing a 243ai- then I decided to buy a cheap short action to use with it. Then I waffles on the short action and decided to save some dough initially and just build on my current 110.

I called Northland Shooters Supply yesterday to discuss the custom throating on Their website and whether they were throated by Shilen or in house. They told me that Shilen's lead time for barrels is 20+ weeks but that they have a .243win barrel in stock that's the same profile and twist I was after anyway.

So I went ahead and bought it. Settled on a SS Select Match 26" Varmint 1:8T.

Let the joy begin. Thanks everybody for advice and guidance.

Yep I love that page and that was a big influence on deciding not to Ackley. I hate trimming brass, which may have been a big plus to the AI, but ultimately I know the standard case should load a little better and get almost as much velocity.

Plus I can easily rechamber it later on if need be.

My original goal was 3100-3200 FPS with either the 103 ELD-X or Berger 105 family. I think I can get there AOK. My encore barrel at 24" can get 3000 from the 103, it just shoots 6 inch groups at 100.

I think you'll be happy. If I didn't already have good Redding dies for the 243 AI I wouldn't have rebarreled to it again. The feeding leaves a lot to be desired, even from AICS mags.

Now that I have a 243 Win and subsequently good dies for that I don't think I'll be doing the AI route again when I burn either my 243 Win or 243 AI barrels out.

Well here's my ugly duckling. Since this rifle really has no purpose, I chose to use mostly what I've got on hand. So my 110 action in .300WM got a new bolt face, and I'm borrowing the stock from my 110 FCS HS in .338LM thus the mile long magazine for a 243. I'll have to single load for now, but I think I'm going to put it in a Boyd's at some point anyway. Anyway- at least I'll get to do some shooting soon.

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Patiently waiting on the range report.

Well I may come back with a better write up than this, but I got out to the range today and things got off to a good start. I did a lazy man's break in by firing 2 3-round groups with some factory Hornady ammo and then half-ass cleaning with some copper solvent. I'm sure I didn't get it all out but whatever. I'm not sold on break in anyway.

Here's the 6 rounds of American Whitetail-


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Next up was some 5 round groups to find a seating depth it likes. I normally tune powder charge first, but I'm trying something new out. I shot 4 groups using virgin Hornady brass, whatever primer they load at the factory, IMR4831, and a 103gr ELD-X. Only change was seating depth from on the lands to -.040. All the groups were encouraging, but the very first one I shot was the -.040 one and it was the best. This clocked in around 2,900 FPS so I'm going to want more.

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I'm super happy so far since this was virgin brass with no prep done. The -.040 load above had an SD of 7, so I'm pretty satisfied with my loading bench process.

You might want to go with a slower powder to get more speed. I worked up a load this morning with IMR 4831 and 105 RDFs in my 243 AI and I'll be happy to get much over 3000-3100 with it. I just happen to have 8 pounds of it on the shelf so I decided to burn it up.

I'd look for something like Reloder 26, H1000, or IMR 7828.

That's a good thought and it's on my list. I have had good luck with 4831 in both 243 and 300WM, so I've always got some around.

I've got some Superformance, but I don't see a lot of folks using it. I tried it in my encore 243 and I couldn't burn it all even with a mag primer. My SDs were all over the place. Plus ball powder is not fun in a rifle for me.

Have you used the IMR enduron powders at all? There's two that bracket H1000 on the burn rate charts.

I haven't. Other than H4350 and 4831sc I mostly use Alliant powder. 16, 23, and 26 being double base temp stable powders that's where I've spent most of my money lately. They're a bit harder on barrels but barrels are cheap and the velocity is worth it IMHO.

I haven't loaded rifle carts with Alliant at all, but my dad has loaded one of them in his 7mm-08 and .30-06 a lot. I'll try to track down some 26 and really crank on this. I want 3100 pretty bad and I'm willing to kill some brass if I have to along the way.

Thread needs rifle pics.

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You won't need to push too hard to get 3100 with 26. And it's the powder I'd use if I was you.

IMR 7828 and 4831 have been good to me in my .243Win with about any primmer I have used.

I am running 115rdfs at 3050 easily with h1000. Probably 100fps left with that powder. Very stable and cool running. ETA 26 inch 7 twist tube.

Thanks for the data point. H1000 is looking to be the way to go- now I just need to find some for sale.

I hit up an out of town bass pro this weekend and grabbed some Hybrid 100V and some 7977 so I'll probably load a few up with that. Still working with the 103 ELD-X for now since I have a small stash.

H4350 or rl16 will get you 3100 easy out of a 26" 243 with 105-107.  42.0-43.3gr h4350, something in that range will shine.  My 243 at load is 43.3 with 107smk and does 3110 and groups in the .1-.2s

For anyone still following-

Very happy with this Shilen prefit. One drawback is that it has the VLD chamber (zero free bore) so I'm a little cramped for powder space. Upside being I have a little more room to grow as things erode. I liked the idea of a long action 243, but with the short throat it looks like I can feed the 105s and 115s to the lands from a SA which is cool too.

Doing some seating depth testing- three different powders and 4 seating depths to see if the powder/charge mattered to seating preference. Ended up being less conclusive than I hoped, but did establish that the 103 ELD-X likes some jump- two powders liked the 2nd shortest length and the third liked the shortest. SDs sucked, but it was virgin brass and so it should only get better.

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