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Discussion in 'Equipment Discussions' started by LOBO, Oct 24, 2005.
What is the average barrel life of the Allen Mags?
while you are answering that would you speak to the amount of barrel that might be lost on setting the barrel back.
P.S. Congratulations on building SS7MM a great gun and to Richard for a great bullet.
Unless something has changed, he has not shot out any barrels yet. He is estimating 1200 rounds at one deer-of-minute at long range.
He has customers that have shot out STWs, and with the powder differences, both burn rate and charge differences, that is how he has them estimated.
In about a year Lerch and I will probably know the bbl life of the 270 AM!!!
I have always been very upfront about the limitations these extreme performance rounds place on barrel life. I have used the best system I have found to extend barrel life as long as possible. These steps include using HEAVY bullets at high velocity instead of light to moderate weight bullets at hyper velocity.
Also, I had Dan Lilja tool up for special barrels, all with 3 groove rifling to offer as much resistance to throat erosion as possible.
Finally, I recommend using the very slow Ball burning powders which are much less abrasive as they pass through the throat as well as burning at a lower flame temp in the bore.
All these combined work together to offer very usible barrel life for a big game rifle which is the only use I have ever recommended the Allen Magnums be used for.
Richard Graves and I are also researching a system which may actually double barrel life!!! It is still in the planning/research and testing stage but if it works the way it is should in theory, not only will there be an increase in performance(velocity potential, unsure how much) but there will be a dramatic increase in barrel life.
From comparing similiar rounds, namely the 257 STW to the 257 Allen Mag, I have predicted that barrel life will be in the 1000-1200 round range, again this is for big game hunting accuracy at extended ranges, not being able to zip a P. dog at 800 yards on the 1200 round down the pipe so keep that in mind.
Barrel life is effected by so many variables that this is really just a guess, how the rifle is used, how it is cleaned, how hard you drive the ammo, all this will effect barrel life.
I rarely run my personal Allen Magnums to full tilt load levels. For example, I load my 257 AM with the 156 gr ULD RBBT to a hair over 3300 fps. If I wanted to I could break 3400 fps but if you run the numbers you will see why I have no problem dropping the load to 3300 fps and barrel and case life will be increased dramatically even with only a 100 fps drop in velocity.
My 270 AM I load the 169.5 gr ULD up to just short of 3300 fps. I am sure you have seen that BJ and Lerch are running 3400-3450 fps which is a top but comfortable load in their personal rifles. As you can see I am well off max but I can hit pretty much anything I want out to 1000 yards with this load so I think very little of the extra 100-150 fps.
If I had to GUESS what the barrel lifes will be with a properly cared for barrel, this is what I would say being conservative as always:
257 Allen Mag...........1000 rounds
270 Allen Mag...........1200 rounds
7mm Allen Mag...........1100 rounds
338 Allen Mag...........900-1000 rounds
With the experimenting we are currently doing, if the system proves to work as predicted, these round counts could possibly double!!!
No hints yet but its very interesting stuff. Just have to design a system that is practical for everyone to use!!
For everyone interested in an Allen round I have also just released two more rounds that I have named the 257 Allen Xpress(AX) and 6.5mm Allen Xpress(AX).
I am actually field testing the 6.5 AX as this is being written. The rifle is based on a stainless Ruger M77 MkII with a 26" Lilja barrel and factory Laminated wood stock.
Its current load is driving the 140 gr Partition to 3320 fps in a true standard length receiver. These new wildcats are not overly bore friendly either but compared to their big brothers, the Allen Magnums, they will offer much more bore life as still outperform most of the 257s and 6.5mm on the market and with the big Wildcat Bullets they will outperform everything except the Allen magnums.
I am going to test the 6.5mm AX on mule deer doe here as soon as the temps drop below 70 degrees here in Montana!!!
Reports to come soon.
Temps above 70 degress in Montana, this time of year /ubbthreads/images/graemlins/shocked.gif
Same here in SE Idaho /ubbthreads/images/graemlins/confused.gif When you get your temp down could you put a word in for down here also.
Its a heck of a deal when the limiting condition on doing some terminal performance tests on those WC 252s is the warm days. Maybe I otta do the test using the neighbor's lamas, wouldn't care so much if that meat spoiled.. /ubbthreads/images/graemlins/crazy.gif
Appreciate the bbl life guestimates. Sound quite reasonable.
Me and BJ are shooting our 270 AM's at 3400-3450 and I know this will probably cut down on our barrel life but i choose this load because I saw my 100yds group tighten up a decent amount when I went from 102 to 104gr of powder. I probably could have done the same thing by playing with the seating depth at 102gr but I am kind of impatient. /ubbthreads/images/graemlins/grin.gif
So Kirby when are you gonna let us test this "new" system in the 270 AM. I sure as hell don't mind being a guiney pig for something this cool /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
take it easy
Thanks for the reply Kirby. Could you tell us some more info on the 257 and 6.5 AX rounds? What boltface do they use? Long or short action?
As you already know, you will be first in line to test this out!!
Basically these two rounds were an idea to get more performance in a standard length action. That being one designed for an OAL of 3.400" which is what the Ruger M77 and Win M70 standard length actions will accept.
The parent case is the 300 Dakota case which is 2.550" in length. The case id modified to the same Allen Magnum configuration in body and shoulder specs.
Being roughly 10 grains less in case capacity then the Allen Magnums, the Allen Xpress rounds will be more user friendly as well. In the 257 AX, the 100 to 120 gr bullets will be much more user friendly then in the big Allen Magnum and still offer at least the same performance as the 257 STW will offer but in a true standard length receiver instead of a long action. In the Rem 700 receiver this will not matter at all but it will offer high performance with slightly longer barrel life. While certainly no where near the equal of the Allen Magnums, the Allen Xpress rounds are still on the top of the performance heap on their respective calibers.
I am currently debating on releasing a 270 Allen Xpress as well but need to do some measuring to see if the longer bullet nose will allow them to be chambered into a standard length receiver. We will see. Would offer 270 STW performance.
The head diameter of the 300 Dakota brass is the same as the RUM except that it has a true 404 Jeffery rim diameter. On the Ruger M77 rifles, there is generally enough room to not require any bolt face opening. The extractor does need to be relieved for this though but thats an easy job. Just a little stoning needed there. Other bolts may need to be relieved slightly but when accurizing a receiver this is a 15 second job since the bolt is already dialed in for machining on the lathe.
In my test rifle, the formed Allen Xpress rounds feed very nicely from the unconverted 7mm Rem Mag based Ruger M77 MkII. It will only accept two rounds in the magazine though for a total payload of 3 rounds with one up the pipe.
Still I don;t know to many guys on this board that ever need more then two rounds at most and generally only one so there are plenty for reserve!!!
Here is the first look at the 6.5mm Allen Xpress. On the left is a 264 Win Mag loaded with the 140 gr A-Max. Middle is the 6.5mm Allen Xpress and on the right is the big 270 Allen Mag loaded with the 140 gr Accubond.
If you have any other questions feel free to ask.
Kirby, The 6.5AX certainly looks impressive, and its release comes at a time when I have been seriously looking at case possibilities for the Krieger 26 inch, 3 contour, 1 in 7 twist 25 cal barrel that I ordered last week. Also, my latest order from Richard includes 125, 130, and 156 grain bullets, and is due to arrive here in Oz in 2 weeks. (Already have some 142)
I have been looking for a rimless case that could provide a case capacity in the 85 - 95 grain range, and is capable of working through a magazine. Hoping to achieve 3250 - 3300 with the 142 grain bullet, and about 3100+ with the 156 grain bullet.
I had been looking at the 6.5m x68mm, 7mm Dakota, 7mm RUM, and even considered the rebated .425 Westley Richards. The 7mm Dakota seemed the best of those options, as it appeared to involve just necking down to .257 without any fireforming or shortening.
This is not meant as a criticism, but I note that you are using the 300 Dakota case, rather than the 7mm Dakota, and wondered what advantages the 300 Dakota case would have offered over the 7mm Dakota. I realise that the 300 Dakota with the .050 extra length would have about 5 - 7 grains (maybe more) extra capacity, but the 7mm Dakota would have been 1 less step in necking down to 6.5 or .257, and also a bit more friendly with magazine length, when using the longest bullets.
I guess that I am a convert to the longer neck design, but the 7mm Dakota has a .333 neck against .310 on the 300 Dakota, and a shoulder angle of 30 degrees against 32 for the 300. It appears from the graphic, that the shoulder of the 300 Dakota has been pushed forward and the neck shortened slightly.
One of the constant criticisms of the Dakota cartridges is the cost of brass, and naturally wondered whether this is likely to continue, or can we expect some relief from current prices in the future.
I commend you on the current initiative and also in the courage you have shown in developing new cases that you believe will benefit the smaller but nonetheless important niche market of long range shooters. I hope that this project succeeds, and at times like this wish I lived in the US, so I could access your services. Good luck, Brian.
I believe Lapua will be making the Dakota brass now. That should prompt some more wildcatting too imo.
sewwhat89, I agree, even if the price of Dakota cases do not fall, if Lapua take over the manufacturing I believe a lot more people will be prepared to use the cases in their rifles. Brian.