LM7 / 2016
7 mm WSM with LM-84 with
84 mm overall Length for small Systems with 762 mm Barrel
LM-84 47 mm long, 10,43 g heavy, BC1000
0,973, for 165 mm Gain twist barrel with
Siehe auch LM7
für die 7 mm Rem Mag für die
Merkel K3 Tar GT
Warning: Smaller Casses (like the 7 mm
RSAUM) than the 7 mm WSM and shorter Barrels fail to obtain the necesary Speed
to stabilize this Bullet. It cannot be shot any slower! Faster is fine.
Six 2,80 mm wide Grooves and corresponding Lands are to be
used. Grouve Diameter shall be 7,21 mm. The Bore is slightly smaller than the
"usual imperial" 7 mm Bore, that typically is 7,04 mm. Also the Groves are
tighter than the "usual German" 7,24 mm Grove Ø. As the Barrels need to be
custom tailored anyway, this should be noticed.
Use preferably a progessive Twist starting from 40 Caliber
length at the Chamber to 20 Caliber at the Muzzle or 280 mm to 140 mm, or 4,5°
to 9° Angle. Is a straight Twist is used, the shorter of the two mußt be used.
If Problems with Drive band shear off should arise, ´those caoul be widened to
accomodate. Please not, this would rise Pressure and Fruction, so while a staig
Twist is possible too, it performs lower and heast more, so is less desirable
The Standard 7 mm WSM Throat suits the
LM-84 not, as the Leade is to long and wide. All other
Dimensions are fine. The LM-84 Throat is 2° full cone
angle, as Europeans say or 1° half Angle from the Cone surface to the Rotation
axis. Coming from the foremost Neck dimension 8,03 mm Ø at 53,59 mm Length from
the Chamber Bottom, out of which the Case bottom sticks 0,1 mm out, a 90° Cone
(full Angle) for 0,36 mm follows. There the 2° Throat starts at 7,32 mm Ø an
then, including the first Cone, reaches for 9,52 mm to the 7 mm Bore.
While a standard 7 mm WSM Reamer may be used for the Case,
either a separate 2° included Angle Throat reamer shall be used, or a Custom
reamer for the 7 mm WSM be employed.
7 mm WSM Cases may be neck turned. If so above Dimensions bust
be accommodated to keep the 2° Throat at the same location with Respect to the
Case, but for the LM-84 this extra Effort is not really
necessary. See below, how the first two Drive bands fit in the 2° Throat:
They are dimensioned to fit with +0,01 mm Space Surface to Surface or 0,02 mm in
Diameter. A Zero Tolerance cannot be designed, as all mechanical Parts are made
with Tolerances, the LM-84 not excepted.
One Millimeter moved a 2° Cone changes 0,035 mm Diameter (above is 10(!) mm
long). So to adjust for 0,02 mm Diameter either the Throat or the Bullet have to
be moved 0,02/0,035 = 0,57 mm or roughly 0,6 mm. That is more than wanted, as
the overall Cartridge length is fixed to 84 mm, hence the Name, so some Gap
might persist. This Gap will allow to unchamber unfired Rounds, if for some
Reason, the intended Shot cannot be fired. So a basic Safety requirement for
Shooting ranges is met.
I am a custom riflemaker out of California U.S.A.. I read about your LM-105 and
LM-84, quite impressive. Would you please let me know your current prices
pre 100 for both lm105 & lm84 and also how longwould it take to deliver them to
LM: Via Email!
My second question is about throat lead angle on LM-84,
you stated 2 degree. Is it 2deg. per side or 2 deg. included angle?
LM: The 2° are included Angle, or 1° per Side. Please read
LOOKING FORWARD HEARING FROM YOU.
RESPECTFULLY, RAY RIGANIAN, Sonntag, 25. Mai 2008 02:07
LM-84 950 m/s Pressure,
click to enlarge
LM-84 950 m/s Pressure Iso-lines,
click to enlarge
LM-84 950 m/s dynamic Pressure contour,
click to enlarge
LM-84 950 m/s dynamic Pressure Iso-lines,
click to enlarge
LM-84 950 m/s Velocity contour,
click to enlarge
LM-84 950 m/s Velocity Iso-lines,
click to enlarge
Estimated Drag, BC and Gyroscopic Stability at Standard ICAO Sea Level Conditions
Möller LM-84 Cal. 7.210 mm, 10.34 g
Ballistic Coefficient Calculated for Drag Function G1
Velocity Drag Coefficient RPM and Stability maximum Twist-
Factor of Form at a Twistlength lenght
and B.C.1 of 22,9 Cal. for s = 1.3
Mach m/s fps Cw i B.C.1 RPM s Cal. in. mm
0,441 150 492 0,072 0,353 0,802 54545 0,92 19,2 5,5 139
0,514 175 574 0,070 0,352 0,805 63636 0,91 19,1 5,4 138
0,588 200 656 0,069 0,347 0,816 72727 0,89 18,9 5,4 136
0,661 225 738 0,069 0,334 0,848 81818 0,86 18,6 5,3 134
0,735 250 820 0,069 0,308 0,919 90909 0,82 18,2 5,2 131
0,808 275 902 0,069 0,270 1,049 100000 0,76 17,5 5,0 126
0,882 300 984 0,073 0,230 1,230 109091 0,66 16,3 4,6 117
0,955 325 1066 0,108 0,264 1,072 118182 0,44 13,3 3,8 96
1,000 340 1116 0,228 0,482 0,586 123743 0,51 14,3 4,1 103
1,102 375 1230 0,195 0,336 0,841 136364 0,59 15,4 4,4 111
1,175 400 1312 0,244 0,392 0,721 145455 0,69 16,7 4,7 120
1,763 600 1969 0,211 0,342 0,828 218182 1,10 21,0 6,0 152
2,351 800 2625 0,174 0,320 0,883 290909 1,25 22,4 6,4 162
2,939 1000 3281 0,148 0,291 0,973 363636 1,33 23,2 6,6 167
3,526 1200 3937 0,127 0,256 1,105 436364 1,38 23,6 6,7 170
4,114 1400 4593 0,111 0,226 1,253 509091 1,42 23,9 6,8 172
4,702 1600 5249 0,099 0,201 1,410 581818 1,45 24,2 6,9 174
5,290 1800 5906 0,089 0,180 1,569 654545 1,48 24,4 6,9 176
Achtung! The LM-84
needs at least 975 Muzzle velocity to fly stable from a 165 mm Gain twist barrel
with an integrated hdp-exhaust, a. k. a.
Recoil brake or Muzzle brake. Noel Carlson will supply such. This Note
means, it will not fly stable from smaller Cartridges, yielding less
Velocity, but from bigger ones. Bigger would not be better, as internal
ballistic Efficiency would drop and too long Barrels would be needed.
That drag minimizing Tail introduced Mac. C. Adams in
Langley, November 1951. M. A. Ramaswamy and S. Viswanathan optimized it December
1975 in Bangalore.
Unfortunately the "Adams tail" has a Drawback. But that can be
taken Care of. Highly energetic expanding Flow at the Muzzle disturb
sharp angled Bottoms, introduce annoying Dispersion.
More, see Muzzle flash
The integrated hdp-Exhaust accommodates the High speed
minimum drag Adams tail at the Muzzle. The Exhaust may be sleeved with a closed
Volume to constitute a recoil and flash absorbing Silencer.
One may ask, why I design so many different shaped
Projectiles. Aren't there optimal Solutions? Yes, there are, but the Conditions
determine the Optimum. Different Conditions yield different Optimization shapes.
This LM-84 is optimized for to deliver 975 m/s Muzzle
velocity from a 7 mm WSM Cartridge out of a 70 cm Barrel. Other Projectiles exit
for other Conditions. The Barrel shall have a progressive, or gain Twist with
final 165 mm Twist length. This slow Twist start is meant to ease Drive bands
requirements to reduce Engraving forces and Friction, but still withstand the
Shear forces for such high Spinning. The ~ 354'278 Revolutions / Minute are fast
indeed. The LM-84
will handle that well.
Lutz Moeller, 4th February 2008
and thanks for information. i know that erkki mäkinen, but is it something else
possible place to get barrels, and how can made right kind of progressive barrel
for special order? (walther, border, krieger, etc). I have seen these mäkinen
maded barrels, and quality doesnt make me "happy",
-sauli- Mittwoch, 2. April 2008 08:00
Border / UK and Gruenig & Elmiger / Switzerland cannot make Gain Twist, unless
they commit large Investments on the Machine + Tooling. They definitely make
very good Barrels, expensive though. Walther, is a different Story. While thy
have also Tool costs for custom Twists, their production is cheaper. Usually
Walther is happy to make 10 custom barrels or more and Prices then become
moderate. I just get a Group for .338" LM Gain twist barrels together.
If You find some Friends to join for a 7 mm LM-84 Project, maybe worldwide, we
can do it easily. For just one Barrel You must have deep Pockets, Walther quoted
4 Months lead time for such a Project. But remember the Bisley ban!
I already have order inside on Border to "8.5"/7mm caliber barrel, because i am
calculated also solid bullets and mean to tested them, when everything is ready.
Those your bullet are very interesting.
I have used free software "WIN GYRO" calculated barrel twists and create right
kind of bullet wich was be enough good stability factors and so good ballistic
coefficient as possible for my knowledge. Material i have mean to bearing
bronze, which is heavier as pure copper. All that basis Berger 10,9 and 11,7 g
VLD bullets, which are quite good long range bullets. Some impulses has get also
.408 Chey Tac bullet also.
7 mm Geschosse in der 7 mm WSM
My target in this is, made bullet which was be enough accuracy
and good ballistic coefficient bullet to long range shooting (BC +.700) and bird
hunting for my own needs.
Beute: Black Grouse, Birkhuhn
Black Grouses hunting by rifle from the top of trees in autumn
after when first ones frost weathers are arrived. Sometimes shooting trips can
be quite long.
Waldrand in 500 m
It is difficult when is small target. Immediately killing area
is about 5cm. Last autumn longest trip was 450 meters, where i got
For few years in dry to found right kind of ready factory bullet, but without
results. Your LM-84 is most near right kind of my needs
what i have found. Some interested i have found but all have being hollow
point bullet and it do not work, when asking bird hunting: It explode
These reasons to i have planning my own solid bullet project
also for few months. Me and couple of my friend, we have private place to shoot,
tested and training always 0 to 1200 meters. Changes which is quite less persons
so good as we.
-Sauli-, Donnerstag, 3. April 2008 08:06
so You used WinGyro (here to be downloaded from my Friend
Peter Jackson`s Page) and reached above
Shapes and Results. I regard that quite an Achievement. Very nice! You Finns
know, how to get along!
Fasan Follow the Link. You shall be surprised!
See also Birkhuhn!
I understand You very well. I once shot a Pheasant (Fasan
Follow the Link. You shall be surprised!) with a Hornady-V-Max not in the Head,
but in the Body and that poor Bird exploded as well. I could use only the Tail
feathers, that I still have to remind me of that Nonsense, I did! You cannot use
fast fragmenting Bullets on small Game and expect any thing else, than an
Now, when Your badly desired Prey is 500 - 1'000 m far away in
the open Landscape, and the vital Range to kill it measures only 5 cm Ø You need
to be a real good Shooter and need extraordinary Gear. As You have comfortably
Possibility to train out to 1'200 m the most important Part, the Shooters
Ability, seems on a good Path to achieve the Task. You
7 mm WSM Cartridge is a quite good Candidate to
launch the tight Bullet, that You found in the LM-84.
The Design goals were little Wind drift on long Ranges, given precise less Wind.
The bigger Brothers have achieved Feat, but with 5 cm Ø in 500 m in Filed
conditions You push the Performance of a Hunting rifle to the Limit.
I assure You with the LM-84
to have found the Optimum, I can think of, and I haven't seen better Bullets
yet. They may be possible, but the Improvements will quite likely only be small.
Read more on the LM-Class page.
Are You and Your Friends the only exotic Finns to hunt the
Black Grouse on such Distances, or is that a common Sport? In Germany they
are quite rare, except for the Alpen Mountains.
How would You like to proceed Sauli?
Thank you for the nice answer in February. I'm rather late to keep in touch, but
even though busy in other areas, some thinking goes on in the background. Of
course, I read with great interest the LM-84
and LM-84 information you pointed me towards.
I did however find that on the LM-84 page the table of
stability calculation seems to have the data for LM-71(!) I hope you can
insert the right data here, I'm looking forward to read it :-)
LM: Actually that was the Case. Thank You for You Report. I
changed those Data to the appropriate LM-84 Stability data.
Also, I wonder about some 9,3 mm KJG calculations. The 9,3 WSM page and 9,3x64
page seem to be based on the exact same bullet (length/weight/splitter/BC
given). Still, in WSM the bullet has a faster initial velocity (1.069 m/s vs
1056 m/s) but slows down faster (300m velocity 770 m/s vs 785 for the 9,3x64).
What exactly goes on here?
It is in the "Flugbahn"
table of each page.
Sorry about the nitpicking. Don't mean to bother you, but I am interested in the
LM: I look into it. The Bullets are clean, as is the Air in
that they fly. No Quirks there! My Web editing on the other Hand may contain
Errors, as we just noticed.
Best regards, Tom K., Mittwoch, 18. Juni 2008 11:38
Hello again Lutz,
I may have found a gentleman to rifle a barrel (or two) for your LM series
bullets. My question has to do with the twist rate you recommend as initial
twist starting at the throat for both the 7 mm LM-84 and 5,6 mm LM-71 bullets. I have
the final twists LM-84 = 165 mm and LM-71 = 135 mm. Also with the gain twist do
you use a straight linear twist increase down the barrel or a parabolic/ramped
increase to give a longer run of slower twist from the throat. Any information
will help as to save any waisted machining cost.
LM: Troy, to start with the half Angle after the Chamber and
linearily gain to full Angle a little before the Muzzle is good Practice.
Also what was the price again for a lot of 100 or 500 of your LM-71 and LM-84
LM: I'll write You.
And, can you ship to USA.
Thanks TROY, Dienstag, 29. Juli 2008 04:34
I have been reading your various web site threads and watching your work on the
.375" and .408" Chey Tac bullets with great interest (I have spoken several
times to Louis Corkern about these projects). As a consequence, I’m extremely
interested in putting together a rife to shoot your 7 mm (LM-84)
and .338 mm (LM-105)
bullets. In that regard, I would like some specific information on what throat
angles I need to use to develop a proper chamber and throat for using these two
bullets. If you have any previously proposed reamer drawings that you are
willing to share, that would be a great help. I would propose to use the LM-84
in a necked down .338 Norma Magnum, and the LM-105s in a .338" LM Improved, so
the velocity should not prove to be a problem. The only issues that I see are
getting the proper throat angle and twist for the barrel, and obtaining the
bullets here in the US.
In addition to Lothar Walther, there is now an American barrel manufacturer –
Bartlein – that will cut a gain
twist barrel of any twist that I might desire. This would solve the gain twist
aspects of the barrel issues that you were talking about with respect to the
.375" LM-119. If my final twist is 7.0” for the
LM-84 and for the LM-105, what would you suggest for the initial twist on the
barrels? I’m just guessing, but would an 8.0” advancing to a 7.0” twist will
work to stabilize these bullets? What length barrel would you suggest for these
bullets and cartridges?
How long would it take to get delivery of 300 or so of the LM-84s and 300 of the
LM-105s? What would the price of such bullets be? Is there anyone here in the
states or Canada presently set up to take delivery of the bullets?
Jeffrey D. VanNiel, Donnerstag, 7. August 2008 15:42
thanks for Your Mail. As I recently wrote in
Twist gain "to start with the half Angle after the
Chamber and linearily gain to full Angle a little before the Muzzle is good
Shipping to Canada is simple. Custom Bullets usually take 6 - 8
Weeks here + 4 Weeks over the Ocean.
Ich habe das Geschoß anfangs im QuickLoad
nicht gefunden, mit einem neuen download Deiner moeller.bul war es auf einmal
drinnen :-). Demnächst wird meine Remington Seven fertig werden, neuer Shilen 56
cm Lauf mit 228,6 mm Drall-Länge, und neues Schmidt & Bender PM II 3-12x50 mit
Mil-Dot 2. Generation. In Amerika schießen die Jungs mit den 7 mm-Short-Kalibern
(7 mm RSAUM und 7 mm WSM) auf den langen und sehr langen Distanzen zum
verblüffen genau, zwar mit
LM: Auf Pappe können Sie damit keinen großen Schaden anrichten
oder jemanden vergiften.
Laut Amerikanern sind die 7 mm Geschosse - der Bleiernen Sippe - jene mit dem
höchsten BC-Wert bei idealem Gewicht (BERGER VLD, CAUTER, JLK VLD oder SIERRA
MATCHKING - 11,34 Gramm bis 12,25 Gramm), also ideal zum Langstreckenschießen,
.30-Geschosse brauchen um so einen BC-Wert zu erreichen zu viel Geschoßmasse,
sind also zu langsam, oder brauchen viiieeel mehr Pulver und sehr lange Läufe um
schnell genug zu werden, und auch die 6,5 mm BC-Werte kommen an die 7 mm
BC-Werte nicht ran.
Anbei 2 QuickLoad-Ladungen mit dem LM-84, aus dem kurzen dicken
(=weniger schwingenden) 560 mm Lauf bis zu 895 m/s schnell bei 100% umgesetzter
Ladung. Denkst du das LM-84 wird mit 228,6 mm Drall ausreichend stabilisiert, da
du in Deiner Netzseite 165 mm Drall empfiehlst?
LM: Fabian, bitte. Du kannst doch lesen. 229 mm sind 39% länger
als 165 mm. Völlig ausgeschlossen. Bei 3,95 längerem Drall würde ich mal rechnen
abe rso ist das völliger Unsinn.
Mich würde nämlich interessieren, auf 1000 Meter (NUR AUF
PAPIER!) genau zu treffen, und das nicht bloß mit einzelnen Zufallstreffern.
LM: Schafts du sicher.
Da es Norma 7 mm RSAUM Hülsen nicht gibt, werde ich nun Norma .300 RSAUM Hülsen
bestellen, und dessen Hals auf 7 mm reduzieren, da Norma nun mal bessere Hülsen
baut als Remington.
LM: Kein Frage. Tatsächlich solltest Du dafür aber bei 7 mm WSM
und 165 mm Drall bleiben. Dafür und für große Weiten ist das
LM-84 nämlich bestimmt - aus langen Läufen.
MfG Fabian, Donnerstag, 3. Juni 2010 13:19
Der Kurzdrall von 165 mm ist für das 47 mm lange LM-84 sicherlich ideal, aber
mein 228.6 mm Drall ist demnach also (leider ?) zu lang. Da ich, um die 1.000
Meter zu versuchen, nicht tausende Euro ausgeben will, werde ich deshalb leider
auf das LM-84 verzichten. Auf der
Jagd wird die nächsten Jahre (so wie es auch die letzten Jahre war) das 31
mm lange 7 mm KJG mein fixer Begleiter!
Mal probieren wie das Lutz Möller KJG auf sehr lange Weiten treffen wird -
vielleicht gar nicht so schlecht, denn wenn es in der Nähe trifft, kann es das
bei guten Bedingungen auf langen Strecken (auf Papier) sicherlich auch, auch
wenn die Winddrift und Flugbahn des LM-84 mit BC-Wert 0.973 alles anderen in den
Vielleicht probier ich auch mal die Bleierne Sippe, denn beim 11,66 Gramm BERGER
VLD (Very Long Drag), BC-Wert 0.659, wird ein 228.6 mm Drall (9“ twist)
empfohlen. Ich werde berichten.
Gruß, Fabian, Freitag, 4. Juni 2010 13:11
Currently (early 2008) Bisley limits fired kinetic Energy to
4'500 Joule. So watch out for local Range limits an Rules to obey.
Dear Mr Moeller,
I am going to build a new rifle for long range shooting in 7 mm
LM: No. Read Warning.
I’d like to use a progressive twist barrel to use your LM84
bullet. I have found a lot of informations in your “LM
class Bullets for windy long ranges”( which is actually unavailable, sub
revision?) , summarizing: cal. 7mm saum, barrel Bartlein/Lilja (the gunsmith is
Kelbly) barrel lenght 32”, 4 drive bands, gain twist from 8,5” to 6,5” to the
muzzle, a separate 2° Angle Throat reamer for a 2 degree full angle cone.
I didn’t neverthless understand what is the correct Twist
angle, I hope you can tell me this one, so I can give to the gunsmith all the
data he needs to make the rifle.
LM: Read Barrel, Twist
Now I need to know how much time you need to make a parcel of
200 and 500 bullets and the price for both.
LM: Custom Ordes no less than 1.000.
I have too a .300 wm rifle and I mean to use its action (a Bat
Machine) to change the barrel for a new 8mm, with the idea to test a 8mm
cartridge for F-Class open matches using a heavvy and fast bullet. I’d like to
use the 8x68s cartridge and your LM 102 bulle (the maximum diameter allowed). I
have read about a wildcat cartridge named “8 x 68 Taras” which you have made but
I didn’t find informations about it. Can you tell me something about this
cartridge? Is it similar or interchangeable with the 8 x 68S? What suggestions
can you give me for this caliber?
LM: That was a Custom Bullet, long Time ago.
I hope you can answer me and I can read in a shorthly time
web site with new informations. Thank you for your attention.
LM: Where will You be able to shoot that Rifle on open Ground in
Italy out to 1.000 m? If You can't, this Project will be bound to fail.
Aldo Franceschin, Treviso, Italy, Sonntag, 1. September 2013