Setting back straight 284

[Keith Glasscock]

I have a 32" straight 284 that is getting long in the tooth - 1500 rounds.

Looking at the bore, it looks to be not bad if I set it back a few inches. I'm thinking that I could end up with a 28" barrel.

My question: Does anyone have experience with a long throated (.220) straight 284 in a 28" barrel? I'm especially interested if H4350 would still provide 2800 fps on 180 hybrids, good accuracy, and without trashing the brass. QL tells me that H4831 would also work, but I'm pretty heavily invested in H4350...

 

[Dusty Stevens]

If its already trashed itll be a good test anyway. I think youll find itll be just fine

 

[ShootDots]

I have a 32" straight 284 that is getting long in the tooth - 1500 rounds.

Looking at the bore, it looks to be not bad if I set it back a few inches. I'm thinking that I could end up with a 28" barrel.

My question: Does anyone have experience with a long throated (.220) straight 284 in a 28" barrel? I'm especially interested if H4350 would still provide 2800 fps on 180 hybrids, good accuracy, and without trashing the brass. QL tells me that H4831 would also work, but I'm pretty heavily invested in H4350...

If it is a 1.250 "straight tube", I would cut about 3" off the chamber end and recrown it>>> I bet you will be back in business! And with 28" you will still get 2775 to 2800 without hurting the primer pockets..

 

[ShootDots]

Man that makes me sad I barely get 2850 from a Shehane with a 30" barrel

I have a friend who used to shoot (disabled now and can't) at Bayou Rifles with us. He had a "straight" .284 on a 32" barrel. He was shooting the Berger 180 VLD's. He had Omar (our riflesmith here) cut 4" off the chamber end and recrown the crown. With, I believe, 56.0grs of IMR 7828 he was topping 2800 f.p.s with better accuracy than when he had the new 32" barrel..

 

[Keith Glasscock]

Ben,

Thanks for that info. I know that I can safely get 2850 or so with slower powder, I'm just trying to determine if I even want to waste the components trying to get a 28" barrel to work that, as Dusty correctly stated is "trashed."

The barrel seems to still be good right now - holds well versus the F-class targets, but I know it will head south soon. I'm trying to do some more fireforming of new brass before it goes away.

My other option is to build the barrel onto a repeater platform as a hunting rifle. If I did that, I'd run lighter bullets.

 

[ShootDots]

Ben,

Thanks for that info. I know that I can safely get 2850 or so with slower powder, I'm just trying to determine if I even want to waste the components trying to get a 28" barrel to work that, as Dusty correctly stated is "trashed."

The barrel seems to still be good right now - holds well versus the F-class targets, but I know it will head south soon. I'm trying to do some more fireforming of new brass before it goes away.

My other option is to build the barrel onto a repeater platform as a hunting rifle. If I did that, I'd run lighter bullets.

If you have access to a GOOD borescope, you can look down the bore to see just how far the firecracking has gone. If it is well into the bore, I would forego any rechamber job and get a barrel. If it looks "pretty decent" and the firecracking is in the first couple of inches, it may well be worth rechambering.. But as far as simply being 28" is concerned, if it is a good shooting barrel, 28" will not be a handicap.

 

[savagedasher]

If the barrel shot good set it back. That is good reason for 32" to start with. Larry

 

[DennisH]

My best with my 284 (last time shot @ 600 yards- 595 out of a possible 600 score)

RL17 was my friend, and I tried almost all powders and RL17 was recommended to me.

Check my Chrono results which stay this consistent when I do my job.

Series 1 Shots: 4
Min 2920 Max 2922
Avg 2921
RL17 52.5grns
9 twist barrel
S-D 1 RL17
ES 2
BR2 CCI
180 Hybrids .050 off
Series Shot Speed
1 1 2922 ft/sec
1 2 2920 ft/sec
1 3 2922 ft/sec
1 4 2920 ft/sec

 

[cdparker]

Conversations with Boots Obermeyer about setting barrels back; he recommends taking off some at the muzzle and recrowning. The gas cutting as the bullet exits the muzzle has an effect on the barrel life just as it does at the breech.
just a thought.

 

[DennisH]

Conversations with Boots Obermeyer about setting barrels back; he recommends taking off some at the muzzle and recrowning. The gas cutting as the bullet exits the muzzle has an effect on the barrel life just as it does at the breech.
just a thought.

Above is correct. You won't see with your eye any difference, but it only takes a few thousandths.

Definitely recrown your barrel if you re-chamber it.

 

[Keith Glasscock]

I was taught to use a pin gauge at the muzzle to determine if any flaring of the bore had occurred. I figured in that I would be taking .25 - .5 at the muzzle.

 

[DennisH]

I was taught to use a pin gauge at the muzzle to determine if any flaring of the bore had occurred. I figured in that I would be taking .25 - .5 at the muzzle.

Keith, it shouldn't be that much, if so, the crown really has a problem. JMO

Dennis

PS: I may take .1 off when I re-crown. I allways liked a 11 deg crown.