Lutz Möller
Munition von der
Lutz Möller GmbH!
Lutz Möller GmbH!
Hello Lutz,
Was a bit amazed about the message on my mobile, (I was 'down' for a while, my
mobile is not my best friend :-))) . I checked and checked but really didn't
receive any emails from you after the mail below. Can you resend them ? Perhaps
you have sent them to another "Ronny" or something ?
Regards, Ronny, Thursday, October 26, 2006 9:00 PM
p.s. Small question : 'progressive' 6.5 mm Lothar walther barrels, are they worth the money ?
Dear Ronny,
Progressive Lothar Walther Barrels give You much less Spin
around the Bore axis then conventional Barrels. Therefore the Rifle moves less.
Therefore You shoot with less Dispersion.
I do not know, how much they charge for that, but I actually talked them into it,
after we won the Lapua Sniper Cup with such a Barrel (for the
LM-105). I only
noticed this beneficial Behaviour after I actually shot the Rifle. I asked
Walther to make it in the first Place to reduce the Torque on the Drive Bands
and never thought about the Spint.
When I first shot the SAKO TRG-42 with progressive LM-105 barrel with 19 g 8,5
mm Bullet from .338" LM I noticed less Twist than my
Heym SR 20 N in 6,5x65 with
7g 6,5 mm Lutz Möller KJG. Now that was a big Surprise:
Less Spin from an almost 3-times heavier Bullet! I discussed that Experience with Walther
Management and pointed out, Sport shooters would enjoy
progressive Twist with
the Advantage to generate less Movement upon the Shot around the Bore Axis i.e.
less Spin than before and therefore would be able to shrink Group sizes. That is
the main Advantage of a Progressive twist barrel against an conventional fixed
twist barrel. You will feel the Difference when You pulled the Trigger and You
will see it on the Target with smaller Groups.
So I am leased to hear, Walther has these progressive Barrels now in the Market
and think, especially with the 6,5 x47 Lapua
Cartridge some new Records are in the Pipe.
May You shoot one?
Sincerely, Lutz
Lutz,
Thank you for the information the your 8mm-.338 Lapua cartridge version 8x70 and LM-101 bullet.
I may do something slightly different, more like an Ackley Improved version. I read more of your very interesting and educational information posted on your web site. I am very interested in the gain twist rifling, and the logic behind it is sound. There are two USA barrel makers, Krieger and Bartlein, that do the cut rifling process (instead of button rifling). They may be able to do the gain twist.
I prefer the four groove rifling over the standard twist because of the lower surface contact area and resulting lower friction. Do you have any opinion on this. Some of the local long range shooters (and Palma) are going to three groove rifling now. Lothar Walther apparently has a proprietary stainless steel for their barrels, maybe improved machineability or better durability over R416, any thoughts there?
Redding has made custom sizing dies for me many times before, and I buy my own custom made chamber reamers. I generally go with my own ideas, but there is so much more information to gain my conversing with knowledgeable people like yourself.
Your bullet design is interesting, among other bullets I use the Barnes MRX and TSX bullets (www.barnesbullets.com).
Best Regards, Richard Saxton, Dienstag, 19. Juni 2007 01:18
Hallo Richard,
According to Erich Stalder of Swiss Grünig & Elmiger Rifle maker
Erich Stalder erdachte die 6,5x47 Lapua
at least with their Method to cut rifle Barrels, You cannot cut progressive gain Twist. I am not to familiar with the Process and would have to call, to have the full Reason explained to me. If You wish, I will do so. On Your side of the Atlantic Ocean, You may ask Krieger and Bartlein, whether they are able to accomplish this.
"We as a team, pride ourselves on our quality of work and products. We strive to be the best in the firearms industry and a world class manufacturer. We have taken Single Point Cut Rifling into the 21st Century."
So one may be able be single and multipoint cut rifle Barrels. If I recall Erich
Stalder right, Grünig & Elmiger cuts on
multiple points the same Time, that being the Reason not to be able to achieve
variable Gain. Actually they use the Multi point process used to keep everything
fixed and repeatable, if my Memory serves me right. Again. I am no Expert in
this Field. I look forward to hear, what Krieger and Bartlein say.
Lothar Walther rifles the Barrels with Button, they press through the bored and honed Barrel, after glowing it in Vacuum to relieve the induced Stress from Machining. By varying the Twist they can achieve a progressive gain twist barrel. A great advantage is the improved Surface You get with this Process. While cut rifled Barrels need to cut undersize and yield a rough Surface to be able to lap this rough Surface to final Dimension, button rifled Barrels are finished right away. Like with hammered Barrels the inner surface is harder too.
The LW50 Lothar Walther Steel for stainless Barrels is 1.4021 martensit Chrome steel. The Difference from of the Shelf 1.4021to LW 50 are the Manufacturing of the Blanks and the Heat treatment, which is not disclosed. After beeing a few hundred Years in the Trade, I just believe the know, what they do and do not tell it anybody. The Result support my Theses so far.
Consider to button rifle a Barrel means to forge some Material, You should consider, where it goes and what remains. Practise has shown the Grooves should not be to wide and Lands not be too thin. So with button rifling larger Bores will have more Grooves and more Lands than smaller ones. Such Restrictions do not apply to cut rifled Barrels, so one has more Freedom there.
Anyhow the gas pressure accelerated Bullet hat to take the Torque from the Lands. So the less Lands You have, the higher the Pressure on the Shaft is and the more likely it will fail to spin. View below Picture, to see how a Desaster looks:
Left a Bullet with sheared off Drive Bands, right another Bullet design with functional Drive bands from the same Barrel
With less and less Lands, You risk to loose the Bullets Ability to take the Torque and spin. Usual "8 mm" Barrels have 7,9 mm Bore and 8,2 mm Grooves and use 4 Lands. In my "8 mm" Case, I use just below 8 mm Bore and 8,2 mm Grove. That means, the Land depth is only 2/3 of the Original. I add 50% more Lands and, guess what, in total I get the same Land area to spin the Bullet, but accommodated to the Button Rifle process an with higher sectional density, hence BC.
Coming to Dies, I have a few Questions to Your Expereince.
How much Diameter differenceYou generally find best between the Chamber and the Sizing Die?
How many different sized Reamers do You have made for
Chamber
Sizer
Seater
Regards Lutz, Waidmannsheil, Lutz Möller,
