I have a 277 AM, but can't seem to get my hands on any heavy-for-caliber, high BC bullets. Next barrel will be in a more common caliber with readily-available lr bullets, such as .308 or .338. Since my bolt face is already opened up for the 338 LM, I will probably stay with the 338 LM brass for the next caliber as well.
At this point, I'm not looking so much for advice on caliber, as I am on what barrel to order. Current set up is Rem 700 action, McMillan A-5, Nightforce NXS 5.5-22. Looking for barrel recommendations on:
Length (28-30") ?
Twist (probaly shooting 250 gr. NAB) ?
Contour (just heavy enough for good lr accuracy - this is a hunting rig) ?
SS or CM ?
anything else you consider important ?
I went with a Rock Creek barrel on my 338 Lapua and I love it. Mine is 30" long and a Sendero contour Carbon wrapped by ABS. A medium Palma Contour Fluted would be about the same wieght and 28" is long enough.
I went with a recomend a 10 twist that will work well with the 250 AccuBond as well as the 300 SMK. The 300 grqin SMK wil have much less wind drift and it is wicked on game
range it,check the wind, dial in correction, aim and only one shot
28-32" depending on MV desired and weight. Each 1" will normally give you maybe 25 fps.
Decide on max weight first. That will drive the diameter and taper.
For example, if weight is not an issue, you could consider the breach going 5 inches and then taper. That allows one complete setback and new chamber. Compare that to a straight taper right off and there is a weight difference of over 8 ounces or more right there.
Dan Lilja has program on his site to figure a blank weight and most of the mftrs will give you info that is accurate within a couple ounces.
The canted rifling (Rock, Obermyer, Border and Broughton) for example seem to give a little more MV compared to standard rifling. I have seen as much as 50-75 fps in my Rock and Broughton barrels.
IMO definetly SS. Just makes sense.
Final twist 9.5 to 10. Cannot go wrong anywhere in there.
Oooh, gain twist. Now that throws a monkey wrench in the system. Peak pressure is at the breach and the tighter the twist the higher the pressure. Bartlein is using a gain twist (starting at say 1-12 and finishing at muzzle at 1-10), that might be a consideration.
Delivery time: check with each barrel mftr. They all run different at different times. One is 6 weeks and the other is 16 weeks. What is your timeframe?
blanks come oversize and you can order a 1.25 blank at max size and it should come out in the neighborhood of 1.27 to 1.28. Talk to the mftr and tell him you want max blank diameter. I would start there and go with straight taper to about .850-.870 if weight is issue.
Fluting is $150-185 normally. Saves 8 ounces. Do you need it?
Thanks for your input, guys. It kind of confirms for me that I am heading in the right direction. Krieger seems to have the lowest pricing right now, but Rock Creek isn't too far behind. Maybe it makes sense to spend a few $$ more to try the 5R rifling from Rock Creek. Any idea on how much ABS charges to carbon wrap your barrel? Do you save weight this way? Is the cost of the wrap offset by the savings on not fluting the barrel?
Looks like it will be a 30" medium Palma tube for me. Trying to keep total weight of the rifle around 13-14 lbs.
Just to throw another wrench in the gears, a new bolt from Dave Kiff at PTG would only be about $150.00 +/- unless you want fluting. Then you could do an Edge or some other .532 bolt face cartridge. That would allow you to sell the 270 AM barrel with a 700 bolt to go with it, If you were planning to sell it.
Just a thought
dirtball, not sure i understand your statement. why would he sell a 532 bolt so he could get another 532 bolt? isn't the 270AM based of the ultra mag case or does it use the Lapua? can't quite keep up with all of the Kirby wildcats.
Kirby's magnums (.30 cal and under) - are based on the 338 Lapua Case. Above .30 cal., the magnums shift to the Cheytac case and the Lapua case is used for his "Express" line. Under .30 cal., the express line is based on the 300 dakota.
If I am not mistaken, the 338 Lapua case was originally based on the 416 Rigby (or Rem 416), while the 7mm/300 RUM case was based on the 404 Jeffries. If I am wrong, please correct.
For me, once I have paid Kirby to accurize an action, it doesn't make sense to break the package up. The 338 Edge and the 338 Lapua are very close ballistically. The Edge is more economical in using Remington brass. The Lapua is more expensive, but it is more accurate and you get more rounds out of it before brass fatigue. Kind of a toss-up. I could go one steo further and have Kirby make me a 300 Allen Express. It is a 338 Lapua that is blown out to "Kirby standards" - kind of like an Ackley Improved version.
Right now, getting the right .338 barrel design & specifications is my primary focus. Once it is ordered and in hand, then choosing caliber will be my next pleasant problem.