243AI vS 257rob

[chet]

ok boys.... here's a debate for us.....
I'm working on a featherweight model 70 for my sons birthday (june)
I have a 20" 257roberts barrel that has perfect headspace on the donor action.
I also have a 22" 243win barrel that would need to be reamed in order to work with this action.
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It would cost me roughly $80 to rent a reamer for the 243 (ackley or std - cost the same)
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I could save that money by using the bob barrel.....
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So for the sake of comparison, lets talk about 100 grain bullets.
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This is a short action, so the OAL of the 257 may suffer - taking up valuable case capacity.
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The 243 will generally have higher BC's
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So will a 22" 243AI with a 100gr pill have a higher muzzle velocity than a 20" 257bob with the same weight bullet?
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maybe some quick load data is in order.
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which would you go with? and why?

 

[truck driver]

I don't think the action length will be a problem for the 257rob with the 100gr bullet but it might effect the 120gr bullets.
If I was to rent a reamer and already had a barrel on the action I would be using I think I would change the 257rob to the 257AI and have the advantage of using heavier bullets.
The 257AI conversion and the 280AI conversion offer the most performance increase in the AI conversions. I believe but I'm not sure that the 257AI with hand loads comes close to 25-06 performance. But then I must admit that I'm not a big 243 anything fan. I had a late 1970's early 1980's Remington Varmint special leave a bad taste in my mouth, lots of money down the tube and visits to the gunsmith for rebedding and still it wouldn't perform as expected. Believe it was a bad barrel but not sure. My friend also has a 243 varmint special that will not out shoot my 257rob.

 

[efw]

I have 2-257s, a standard & an AI which was my first custom rifle. My eldest son's first CF was a 257 Rob. I love me some Bob action.

In my 257 AI w/ 24" barrel & long throat (it's on a Czech Mauser) I typically get around 3300 fps w/ 100s though I have extremely accurate loads that go 3330 & 3250. I haven't ever given much consideration to heavier bullets... 100s are the bread & butter of the quarter-bores, and particularly with the 90 gr GMX & 100 gr TTSX/ETips bigger is superfluous.

That having been said a 243 AI will provide substantial advantages at long range (>400 yds) but I doubt there is a deer alive that'd know the difference between a 100 gr NPT or 90 gr monometal from either cartridge at lesser range.

The thing that makes the decision easy for me is muzzle blast. I hate muzzle blast. HATE. It is more bothersome to me that recoil. I have to believe that a 20" Bob is gonna bark pretty good, but a 22" 243AI (or not AI'd for that matter) will be even worse.

I had a 22" barreled 243 Win that really got yer attention. My son's 257 Rob has 22" and isn't bad at all, though I must admit we don't stoke it to full capacity like I do mine. My Standard Bob is 21" and I charge it fully but it isn't as bad as that 243.

If it were for me I'd do 243 AI but for a kid I'd do the Bob.

 

[SJB358]

6 and 1/2 dozen Chet. Both would be excellent. I run a 243 in a 20" barrel (son's 243 actually). Does real well with 105 Amaxs, 100 PT's, 95 BT and 90 AB's. Just haven't found anything that doesn't shoot well. The 257 would be great with any bullet as Eric mentioned too. I wouldn't both with AI'ing either unless your dieing to gain a little speed with fireforming.

Either one is going to be a slick rifle.

 

[chet]

I've decided on the 257....... although I don't really know why??????? Hahahahahahaaha

 

[Guy Miner]

Good choice!

Then again, they were both good choices... :grin:

 

[Oldtrader3]

To compare the 6mm to the .257, you might consider using sectional density against similar sectional density, The 90 grain 6mm and the 100 grain .257 have almost identical (.216 vs. .218) SD but the .257 is higher in ballistic coefficient (.365 vs. .393) for the .257. Muzzle velocities will be similar, at least using IMR 4350 they will.

To me, running a 6mm in a 20 inch barrel loses about 100 fps or a little more versus the 24 inch on my .257 Mauser. Plus the higher ballistic coefficient cost you some more velocity in the .243 AI at longer range. If you are willing to pay that price, then by all means buy the AI. However, my freebored, full length action .257 Roberts gives me about 3150 from a 24 inch barrel with 110 gr Accubonds and a BC well over .400. For those reasons, I prefer the .257 Roberts and the longer barrel with full length action.

 

[Divernhunter]

For hunting larger game(deer/elk/pigs/pronghorns/Africain plains game) the 257Roberts would be a better choice.
For PD or squirrels the 243 might be better.

 

[mtwarych]

I have witnessed a 257 rob kill 2 elk with 120 grn nos partitions on top of a full load of H4831.
The rifle is a ruger m77 lightweight with a 20" barrel. Both elk were shot at about 260 yards and both died within feet of the impact.
You probably realize I am voting for the 257.
Nobody loves the quarters anymore.
Both elk were killed by 12 year olds.

 

[SJB358]

I have witnessed a 257 rob kill 2 elk with 120 grn nos partitions on top of a full load of H4831.
The rifle is a ruger m77 lightweight with a 20" barrel. Both elk were shot at about 260 yards and both died within feet of the impact.
You probably realize I am voting for the 257.
Nobody loves the quarters anymore.
Both elk were killed by 12 year olds.

Your in a good place buddy. Lotsa love for the .257's around here. Most of us that don't have one, want one!

 

[mtwarych]

It is kind of silly, but my favorite rifle is my 257 rob. The rifle is just a pleasure to shoot and it covers everything from rats to elk in our case.

 

[SJB358]

It is kind of silly, but my favorite rifle is my 257 rob. The rifle is just a pleasure to shoot and it covers everything from rats to elk in our case.

Nothing silly about confidence in a rifle. Might mean more than any other factor out there.

 

[Oldtrader3]

True dat. I have been using the .270 Win for 50 years. It is not the most powerful rifle in the safe but it delivers DRT every time for me. That confidence factor is still critical when the chips are down, as Scotty said.

 

[Oldtrader3]

I have to say that the new bullet issues of Partitions and Accubonds in 110 grain and 115 grain have clinched it for me with the .257 Roberts. Especially the rifle that I have chambered for .257 Roberts with the full length magazine, action and some freebore. I am able to get performance that none of my previous .257 Robert's were able to attain. These newer bullets make the Roberts an all around deer rifle.