300:(250 ft⋅lbf). Due to the combination of a thin-walled rimfire case with a high-pressure powder charge, the cartridge needed good external support so the MKR rifle was designed to use locked breech, gas-operated action with a vertically tilting bolt rather than straight blow back operation. This ensured the bolt only opened once cartridge pressure had reduced to safe levels. The rifle and carbine, which differed only in barrel length, were fired from the open bolt position to prevent cook-off ignition of the thin walled cartridges. Users could select from semi-automatic, three-round burst, or fully automatic modes. The burst and fully automatic modes had a high rate of fire of 1800 rounds per minute.
313:
NATO with M-193 projectile. This was due to a combination of slightly higher velocity, a similar
Ingalls ballistic coefficient to the M-193 bullet (0.245 vs 0.265), and the superior penetrating ability of solid cold-rolled copper bullets vs jacketed lead bullets given an equal sectional density. It was potentially lethal at up to 750 m (2,460 ft) with 80 J (59 ft⋅lbf) and its tendency to tumble on impact was twice that of the 5.56 M-193 bullet, thus ensuring more effective transfer of its diminutive energy to its target, especially as its tip tended to bend. Maximum range was 2,500 m (8,200 ft).
31:
483:
816:
295:
rifle and carbine. It was supplied in single-use, 50-round polymer magazines. The cartridge featured a curved taper of its body to aid extraction and a short, shoulderless neck. Its 4.5 mm (0.18 in) caliber boat-tail spitzer bullet was 22 mm (0.87 in) long and made by cold rolling
312:
M-193 bullet at up to 300 m (980 ft), while one could carry 3.5 times as many of the lighter weight cartridges. Its slender 4.5 mm (0.18 in) projectile could penetrate a steel helmet up to 300 m (980 ft), out to that range it had a similar ballistic curve to the 5.56×45
278:
The 4.5mm MKR was designed in 1978 by
Interdynamic AB, a Swedish company, around the time of the rise of "micro-caliber" popularity. Firearms companies everywhere were trying to achieve a type of practical, light and cheap ammunition. Micro-caliber (less than 5 mm (0.20 in) in diameter)
299:
The lightweight bullet of 1.58 g (24.4 gr) reportedly achieved a muzzle velocity of about 1,000 m/s (3,300 ft/s) and a muzzle energy of 790 J (580 ft⋅lbf). This claim contrasts sharply with the comparable, more modern .17 HMR which has a muzzle energy of 340 J
316:
Due to concerns about stopping power, reliability, and the inherent problems with using rimfire ammunition, the MKR project was abandoned at the prototype stage and the 4.5mm MKR never saw service or any kind of widespread use.
279:
ammunition makers wished to achieve higher velocities, flatter trajectories, and greater penetration while keeping weight and recoil low as possible to facilitate controllable use in individual automatic weapons.
637:
630:
998:
422:
30:
623:
765:
745:
400:
368:
291:
rimfire case necked down from 5.6 mm (0.22 in) to accept a 4.5 mm (0.18 in) bullet, for use in the
790:
462:
1003:
710:
675:
415:
863:
720:
652:
527:
508:
730:
585:
680:
615:
491:
848:
735:
725:
967:
909:
838:
937:
932:
408:
386:
439:
267:
917:
522:
760:
740:
309:
292:
472:
972:
665:
800:
660:
957:
40:
36:
947:
927:
590:
551:
532:
517:
457:
992:
833:
580:
873:
868:
770:
431:
200:
0.51 grams tubular nitrocellulose powder or 0.57 grams spherical double-base powder
600:
270:
developed for the prototype
Interdynamics MKR bullpup assault rifle and carbine.
952:
898:
853:
795:
595:
575:
351:
750:
690:
570:
447:
755:
695:
977:
942:
893:
542:
432:
Cartridges with bullet diameter between 4 mm (0.16 in) and 5 mm (0.20 in)
805:
780:
775:
705:
670:
504:
482:
452:
326:
288:
118:
962:
888:
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878:
858:
843:
825:
785:
715:
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685:
500:
815:
561:
619:
404:
136:
4.63 mm, 22 mm long, cold-rolled copper, boat-tail spitzer.
23:
646:
Modern personal defense weapons (PDWs) and cartridges
907:
823:
651:
560:
541:
499:
490:
438:
204:
196:
188:
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172:
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156:
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114:
109:
98:
90:
82:
77:
69:
64:
56:
48:
21:
346:
344:
342:
308:The 4.5×26 MKR was claimed to be on par with a
631:
416:
8:
638:
624:
616:
496:
423:
409:
401:
387:"Wymiary łusek - Forum Broni Strzeleckiej"
29:
128:Rimfire, tapered, shoulderless bottleneck
338:
363:
361:
18:
7:
716:GAU-5A Aircrew Self Defense Weapon
14:
16:Swedish prototype rifle cartridge
814:
766:Joint Venture Protective Carbine
481:
287:The 4.5mm MKR was essentially a
236:1,000 m/s (3,270 ft/s
352:"4,5x26R : Guns / Metric"
99:
1:
746:Knight's Armament Company PDW
706:FN SCAR PDW & FN SCAR SC
999:Pistol and rifle cartridges
791:Saab Bofors Dynamics CBJ-MS
731:Heckler & Koch MP5K-PDW
463:.17 Winchester Super Magnum
233:1.58 g (24.4 gr)
1020:
726:Heckler & Koch G11 PDW
711:GA Personal Defense Weapon
266:, was a Swedish prototype
248:Test barrel length: 640 mm
839:FK BRNO Field Pistol, PSD
812:
479:
247:
238:
227:
224:
221:
217:
213:
209:
57:Place of origin
28:
676:Brügger & Thomet MP9
653:Personal defense weapons
721:Gepard (submachine gun)
849:Heckler & Koch UCP
736:Heckler & Koch MP7
586:.17 Remington Fireball
149:Shoulder diameter
681:Bushmaster Arm Pistol
492:Centerfire cartridges
205:Ballistic performance
258:, also known as the
184:42 mm overall length
133:Bullet diameter
375:. October 27, 2010.
369:"Interdynamics MKR"
296:solid copper wire.
181:Overall length
440:Rimfire cartridges
260:4.5mm Interdynamic
239:790 J (583 ft lbs)
157:Base diameter
141:Neck diameter
78:Production history
1004:Weapons of Sweden
986:
985:
761:Interdynamics MKS
741:Interdynamics MKR
613:
612:
609:
608:
293:Interdynamics MKR
268:rimfire cartridge
252:
251:
243:
242:
165:Rim diameter
1011:
938:5.56×30mm MINSAS
933:5.56×21mm PINDAD
818:
666:AAC Honey Badger
640:
633:
626:
617:
497:
485:
425:
418:
411:
402:
395:
394:
383:
377:
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365:
356:
355:
348:
222:Bullet mass/type
219:
218:
189:Primer type
173:Case length
115:Parent case
101:
94:Interdynamics AB
73:Prototypes only.
33:
24:
19:
1019:
1018:
1014:
1013:
1012:
1010:
1009:
1008:
989:
988:
987:
982:
918:4.38×30mm Libra
903:
819:
810:
806:SIG MCX Rattler
801:ST Kinetics CPW
647:
644:
614:
605:
556:
537:
523:4.38×30mm Libra
486:
477:
434:
429:
399:
398:
385:
384:
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373:Modern Firearms
367:
366:
359:
350:
349:
340:
335:
323:
306:
285:
276:
264:4.5mm Kjellgren
105:Prototypes only
65:Service history
44:
22:
17:
12:
11:
5:
1017:
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1007:
1006:
1001:
991:
990:
984:
983:
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965:
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953:5.8×21mm DAP92
950:
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598:
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591:.17 Ackley Bee
588:
583:
578:
573:
567:
565:
558:
557:
555:
554:
552:.17 Bumble Bee
548:
546:
539:
538:
536:
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530:
525:
520:
518:4.25mm Liliput
514:
512:
494:
488:
487:
480:
478:
476:
475:
470:
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458:.17 PMC/Aguila
455:
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391:strzelecka.net
378:
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310:5.56×45mm NATO
305:
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125:Case type
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110:Specifications
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4:
3:
2:
1016:
1005:
1002:
1000:
997:
996:
994:
979:
976:
974:
973:9×21mm Gyurza
971:
969:
966:
964:
961:
959:
958:6.5×25 CBJ-MS
956:
954:
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949:
946:
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845:
842:
840:
837:
835:
834:FN Five-seven
832:
831:
829:
827:
822:
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802:
799:
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789:
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769:
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764:
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629:
627:
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599:
597:
594:
592:
589:
587:
584:
582:
581:.17 Remington
579:
577:
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572:
569:
568:
566:
563:
559:
553:
550:
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547:
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407:
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392:
388:
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364:
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81:
76:
72:
68:
63:
59:
55:
51:
47:
42:
38:
32:
27:
20:
968:9×19 mm 7N31
923:4.5×26mm MKR
922:
874:PSA 5.7 Rock
869:Pindad PS-01
824:PDW-caliber
771:PP-19 Vityaz
468:4.5×26mm MKR
467:
390:
381:
372:
315:
307:
298:
286:
277:
263:
259:
255:
253:
152:Shoulderless
91:Manufacturer
43:, 4.5×26MKR.
41:5.56×45 NATO
37:7.62×51 NATO
948:FN 5.7×28mm
928:HK 4.6×30mm
899:SR-1 Vektor
864:M&P 5.7
854:Kel-Tec P50
796:SR-2 Veresk
576:.17 Mach IV
533:4.6×30mm HK
304:Performance
102: built
993:Categories
910:cartridges
751:Magpul PDR
571:.17 Hornet
564:cartridges
545:cartridges
511:cartridges
448:.17 Mach 2
333:References
70:In service
696:Floro PDW
601:4.85×49mm
528:4.5×40mmR
256:4.5mm MKR
35:L to R:
943:.224 Boz
894:Ruger-57
596:4.6×36mm
543:Revolver
321:See also
225:Velocity
176:26.10 mm
83:Designed
826:pistols
781:PP-90M1
776:PP-2000
691:ČZW-438
671:AKS-74U
505:carbine
473:4mm M20
453:.17 HMR
327:.17 HMR
289:.22 WMR
274:History
197:Filling
192:Rimfire
168:7.44 mm
160:6.48 mm
144:5.02 mm
119:.22 WMR
978:9×39mm
963:7.5 FK
889:QSZ-11
884:QSZ-92
879:QSW-06
859:MP-443
844:GSh-18
786:QCW-05
701:FN P90
501:Pistol
283:Design
228:Energy
60:Sweden
686:CF-05
661:AO-46
562:Rifle
52:Rifle
908:PDW
756:MARS
507:and
254:The
86:1978
49:Type
509:PDW
262:or
100:No.
995::
503:,
389:.
371:.
360:^
341:^
39:,
639:e
632:t
625:v
424:e
417:t
410:v
393:.
354:.
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