±Recent Visitors

Recent Visitors to Com-Central!

±User Info-big


Welcome Anonymous

Nickname
Password

Membership:
Latest: HighestAce
New Today: 0
New Yesterday: 0
Overall: 6648

People Online:
Members: 0
Visitors: 872
Total: 872
Who Is Where:
 Visitors:
01: Home
02: Downloads
03: Photo Gallery
04: Member Screenshots
05: Home
06: Photo Gallery
07: Community Forums
08: Member Screenshots
09: Home
10: Photo Gallery
11: Member Screenshots
12: Member Screenshots
13: Home
14: Downloads
15: Home
16: Community Forums
17: Photo Gallery
18: Your Account
19: Community Forums
20: Home
21: Community Forums
22: Home
23: Member Screenshots
24: Photo Gallery
25: Downloads
26: Home
27: Photo Gallery
28: Photo Gallery
29: Downloads
30: Downloads
31: Photo Gallery
32: Photo Gallery
33: Photo Gallery
34: Community Forums
35: Community Forums
36: Photo Gallery
37: Community Forums
38: Community Forums
39: Home
40: Home
41: Home
42: Downloads
43: Member Screenshots
44: Community Forums
45: Downloads
46: Community Forums
47: Downloads
48: Home
49: News Archive
50: Photo Gallery
51: Home
52: Downloads
53: Community Forums
54: Community Forums
55: Community Forums
56: Home
57: Home
58: Downloads
59: Home
60: Member Screenshots
61: Home
62: Community Forums
63: Home
64: Photo Gallery
65: Community Forums
66: Community Forums
67: Home
68: Photo Gallery
69: Photo Gallery
70: Community Forums
71: Community Forums
72: Home
73: Photo Gallery
74: Downloads
75: Home
76: Photo Gallery
77: Home
78: Community Forums
79: Photo Gallery
80: News
81: Photo Gallery
82: Home
83: Home
84: Downloads
85: Photo Gallery
86: Home
87: Contact
88: Photo Gallery
89: Photo Gallery
90: Photo Gallery
91: Photo Gallery
92: Community Forums
93: Photo Gallery
94: Member Screenshots
95: Downloads
96: Community Forums
97: Photo Gallery
98: Community Forums
99: Home
100: Photo Gallery
101: Photo Gallery
102: Community Forums
103: Member Screenshots
104: Home
105: Member Screenshots
106: Photo Gallery
107: Photo Gallery
108: Community Forums
109: Community Forums
110: Photo Gallery
111: Home
112: Photo Gallery
113: Statistics
114: Home
115: Statistics
116: Photo Gallery
117: Photo Gallery
118: Photo Gallery
119: Community Forums
120: Photo Gallery
121: Photo Gallery
122: Photo Gallery
123: Member Screenshots
124: Photo Gallery
125: Photo Gallery
126: Home
127: Statistics
128: Members List
129: Photo Gallery
130: Photo Gallery
131: Photo Gallery
132: Photo Gallery
133: Community Forums
134: Photo Gallery
135: Photo Gallery
136: Member Screenshots
137: Community Forums
138: Home
139: Photo Gallery
140: Community Forums
141: Community Forums
142: Photo Gallery
143: Home
144: Photo Gallery
145: Home
146: Downloads
147: Downloads
148: Home
149: Community Forums
150: Community Forums
151: Community Forums
152: News
153: Community Forums
154: Photo Gallery
155: Community Forums
156: Home
157: Home
158: Photo Gallery
159: Home
160: Home
161: Photo Gallery
162: Photo Gallery
163: Member Screenshots
164: Home
165: Photo Gallery
166: Community Forums
167: Photo Gallery
168: Photo Gallery
169: Home
170: Community Forums
171: Home
172: Community Forums
173: Community Forums
174: Community Forums
175: Community Forums
176: Community Forums
177: Member Screenshots
178: Community Forums
179: Home
180: Photo Gallery
181: Community Forums
182: Home
183: Community Forums
184: Community Forums
185: Photo Gallery
186: Photo Gallery
187: Community Forums
188: Home
189: Community Forums
190: News Archive
191: Downloads
192: Home
193: Home
194: Photo Gallery
195: Statistics
196: News Archive
197: Community Forums
198: Community Forums
199: Statistics
200: Community Forums
201: Home
202: Photo Gallery
203: Photo Gallery
204: Home
205: Member Screenshots
206: Community Forums
207: Community Forums
208: Home
209: Statistics
210: Home
211: Downloads
212: Downloads
213: Home
214: Home
215: Community Forums
216: News Archive
217: Downloads
218: Home
219: Home
220: Home
221: Home
222: Community Forums
223: News Archive
224: Home
225: Home
226: Community Forums
227: Photo Gallery
228: Community Forums
229: Statistics
230: Downloads
231: Home
232: Home
233: Home
234: Home
235: Home
236: Home
237: Home
238: Home
239: Home
240: Home
241: Downloads
242: Home
243: Photo Gallery
244: Photo Gallery
245: Home
246: News Archive
247: Photo Gallery
248: Photo Gallery
249: Downloads
250: Downloads
251: Community Forums
252: Downloads
253: Home
254: Downloads
255: Community Forums
256: Photo Gallery
257: Home
258: Statistics
259: Home
260: Photo Gallery
261: Community Forums
262: Photo Gallery
263: Community Forums
264: Home
265: Photo Gallery
266: Community Forums
267: Home
268: Home
269: Home
270: Photo Gallery
271: Community Forums
272: Community Forums
273: Home
274: Home
275: Photo Gallery
276: Home
277: Home
278: Home
279: Home
280: Home
281: Home
282: Home
283: Home
284: Home
285: Home
286: Home
287: Community Forums
288: Home
289: Community Forums
290: Home
291: Community Forums
292: Home
293: Photo Gallery
294: Home
295: Home
296: Photo Gallery
297: Photo Gallery
298: Home
299: Home
300: Home
301: Downloads
302: Home
303: Home
304: Community Forums
305: Downloads
306: Home
307: Home
308: Photo Gallery
309: Community Forums
310: Photo Gallery
311: Community Forums
312: News Archive
313: Home
314: Home
315: Photo Gallery
316: Photo Gallery
317: Your Account
318: Community Forums
319: Photo Gallery
320: Home
321: Photo Gallery
322: Photo Gallery
323: Photo Gallery
324: Community Forums
325: Home
326: Photo Gallery
327: Downloads
328: Home
329: Home
330: Home
331: Home
332: Home
333: Home
334: Community Forums
335: Home
336: Home
337: Home
338: Home
339: News
340: Home
341: Member Screenshots
342: Home
343: Photo Gallery
344: Home
345: Home
346: Community Forums
347: Home
348: Home
349: Home
350: Home
351: Community Forums
352: Home
353: Home
354: Community Forums
355: Photo Gallery
356: Photo Gallery
357: Home
358: Home
359: Home
360: Photo Gallery
361: Photo Gallery
362: Home
363: Photo Gallery
364: Your Account
365: Home
366: Community Forums
367: Community Forums
368: News Archive
369: Home
370: Home
371: Home
372: Downloads
373: Photo Gallery
374: Home
375: Home
376: News Archive
377: Photo Gallery
378: Photo Gallery
379: Home
380: Community Forums
381: Home
382: Community Forums
383: Home
384: Home
385: Home
386: Member Screenshots
387: Member Screenshots
388: Community Forums
389: Home
390: Home
391: Community Forums
392: Home
393: Home
394: Home
395: Home
396: Home
397: Home
398: Home
399: Home
400: Home
401: Home
402: Home
403: Home
404: Community Forums
405: Home
406: Home
407: Home
408: Home
409: Member Screenshots
410: News Archive
411: News Archive
412: Photo Gallery
413: Community Forums
414: Community Forums
415: Photo Gallery
416: Community Forums
417: Photo Gallery
418: Home
419: Home
420: Home
421: Home
422: Home
423: Home
424: Home
425: Home
426: Home
427: Home
428: Photo Gallery
429: Photo Gallery
430: Home
431: Home
432: Community Forums
433: Downloads
434: Community Forums
435: Downloads
436: Photo Gallery
437: Community Forums
438: Home
439: Home
440: Community Forums
441: Community Forums
442: Statistics
443: Community Forums
444: Downloads
445: Community Forums
446: Photo Gallery
447: Downloads
448: Member Screenshots
449: Home
450: Home
451: Downloads
452: Home
453: Home
454: Downloads
455: Community Forums
456: Home
457: Home
458: Home
459: Photo Gallery
460: Home
461: Home
462: Home
463: Home
464: Home
465: Home
466: Home
467: Member Screenshots
468: Home
469: Home
470: Home
471: Home
472: Home
473: Downloads
474: Community Forums
475: Community Forums
476: News Archive
477: Home
478: Home
479: Photo Gallery
480: Home
481: Photo Gallery
482: Home
483: Home
484: Photo Gallery
485: Home
486: Community Forums
487: Community Forums
488: Community Forums
489: Tell a Friend
490: Home
491: Photo Gallery
492: Home
493: Community Forums
494: Photo Gallery
495: Home
496: Your Account
497: Photo Gallery
498: Home
499: Downloads
500: Home
501: Home
502: Community Forums
503: Home
504: Photo Gallery
505: Photo Gallery
506: Home
507: Community Forums
508: Member Screenshots
509: Community Forums
510: Community Forums
511: Photo Gallery
512: Home
513: Home
514: Home
515: Home
516: Photo Gallery
517: Home
518: Home
519: Home
520: Downloads
521: Community Forums
522: Home
523: Community Forums
524: Photo Gallery
525: Member Screenshots
526: Photo Gallery
527: Photo Gallery
528: Home
529: Home
530: Home
531: Home
532: Home
533: Community Forums
534: Community Forums
535: Community Forums
536: Community Forums
537: Community Forums
538: Community Forums
539: Community Forums
540: Your Account
541: Community Forums
542: Community Forums
543: Home
544: Home
545: Downloads
546: Community Forums
547: Community Forums
548: Photo Gallery
549: Community Forums
550: Member Screenshots
551: Contact
552: News
553: Home
554: Home
555: Photo Gallery
556: Member Screenshots
557: Home
558: Your Account
559: Home
560: Home
561: Community Forums
562: News Archive
563: Your Account
564: Community Forums
565: Photo Gallery
566: Home
567: Downloads
568: Member Screenshots
569: Community Forums
570: Member Screenshots
571: Home
572: Home
573: Downloads
574: Home
575: Community Forums
576: Downloads
577: Community Forums
578: News
579: News Archive
580: Photo Gallery
581: Photo Gallery
582: News Archive
583: Photo Gallery
584: Home
585: Downloads
586: Community Forums
587: Photo Gallery
588: Community Forums
589: Downloads
590: Community Forums
591: Photo Gallery
592: Photo Gallery
593: Photo Gallery
594: Home
595: Community Forums
596: Home
597: Photo Gallery
598: Statistics
599: Home
600: Community Forums
601: Downloads
602: Home
603: Home
604: Home
605: Home
606: Home
607: Home
608: Home
609: Photo Gallery
610: Community Forums
611: Photo Gallery
612: Home
613: Photo Gallery
614: Community Forums
615: Home
616: Your Account
617: News Archive
618: Photo Gallery
619: Home
620: Photo Gallery
621: Downloads
622: Home
623: Community Forums
624: Home
625: Photo Gallery
626: Home
627: Home
628: Downloads
629: Photo Gallery
630: Photo Gallery
631: Photo Gallery
632: Photo Gallery
633: Photo Gallery
634: Home
635: Photo Gallery
636: Member Screenshots
637: Home
638: Photo Gallery
639: Photo Gallery
640: Photo Gallery
641: News
642: Community Forums
643: Downloads
644: Home
645: Community Forums
646: Photo Gallery
647: Member Screenshots
648: Photo Gallery
649: Downloads
650: Photo Gallery
651: Community Forums
652: Photo Gallery
653: Downloads
654: Community Forums
655: Photo Gallery
656: Photo Gallery
657: Home
658: Member Screenshots
659: Photo Gallery
660: Home
661: Community Forums
662: Community Forums
663: Downloads
664: Statistics
665: Member Screenshots
666: Home
667: Photo Gallery
668: Community Forums
669: Home
670: Member Screenshots
671: Photo Gallery
672: Home
673: Community Forums
674: Home
675: Community Forums
676: Home
677: Home
678: Downloads
679: Photo Gallery
680: Photo Gallery
681: Member Screenshots
682: Home
683: Photo Gallery
684: Photo Gallery
685: Member Screenshots
686: Community Forums
687: Community Forums
688: Home
689: Home
690: Community Forums
691: Home
692: Photo Gallery
693: Home
694: Photo Gallery
695: News Archive
696: Photo Gallery
697: Community Forums
698: Community Forums
699: Home
700: Photo Gallery
701: Home
702: Community Forums
703: Member Screenshots
704: Photo Gallery
705: Statistics
706: Photo Gallery
707: Photo Gallery
708: Downloads
709: Photo Gallery
710: Community Forums
711: Home
712: Photo Gallery
713: Member Screenshots
714: Photo Gallery
715: Community Forums
716: Downloads
717: News
718: Downloads
719: Photo Gallery
720: Community Forums
721: Member Screenshots
722: Member Screenshots
723: Photo Gallery
724: Community Forums
725: Downloads
726: Community Forums
727: Photo Gallery
728: News Archive
729: Home
730: News
731: Photo Gallery
732: Community Forums
733: Statistics
734: Downloads
735: Community Forums
736: Community Forums
737: Home
738: Photo Gallery
739: Home
740: News Archive
741: Home
742: Community Forums
743: Community Forums
744: Photo Gallery
745: Home
746: Home
747: Home
748: News
749: Home
750: Community Forums
751: Community Forums
752: Home
753: Community Forums
754: Photo Gallery
755: Downloads
756: Home
757: Photo Gallery
758: Photo Gallery
759: Downloads
760: Statistics
761: Photo Gallery
762: Downloads
763: Downloads
764: Home
765: News Archive
766: Home
767: Home
768: Community Forums
769: Photo Gallery
770: News
771: Community Forums
772: Community Forums
773: News Archive
774: Member Screenshots
775: Photo Gallery
776: Community Forums
777: Community Forums
778: Photo Gallery
779: News
780: Photo Gallery
781: Photo Gallery
782: Downloads
783: Community Forums
784: Community Forums
785: Community Forums
786: Photo Gallery
787: Community Forums
788: Home
789: Home
790: Community Forums
791: Community Forums
792: Community Forums
793: Downloads
794: Home
795: Home
796: Downloads
797: Community Forums
798: Community Forums
799: Photo Gallery
800: Community Forums
801: Home
802: Home
803: Downloads
804: Community Forums
805: Photo Gallery
806: Home
807: Photo Gallery
808: Community Forums
809: Community Forums
810: Community Forums
811: Community Forums
812: Photo Gallery
813: Photo Gallery
814: Member Screenshots
815: Home
816: Home
817: Community Forums
818: Community Forums
819: Home
820: Community Forums
821: Statistics
822: Home
823: Community Forums
824: Home
825: Community Forums
826: Community Forums
827: Community Forums
828: Home
829: Home
830: Photo Gallery
831: Community Forums
832: Member Screenshots
833: Home
834: Photo Gallery
835: Home
836: Statistics
837: Home
838: Home
839: Photo Gallery
840: Home
841: Photo Gallery
842: Photo Gallery
843: Photo Gallery
844: Home
845: Photo Gallery
846: Downloads
847: Downloads
848: Community Forums
849: Photo Gallery
850: Community Forums
851: Member Screenshots
852: Home
853: Community Forums
854: Community Forums
855: Community Forums
856: Photo Gallery
857: Community Forums
858: Community Forums
859: Home
860: Photo Gallery
861: Home
862: Photo Gallery
863: Home
864: Downloads
865: Community Forums
866: Photo Gallery
867: Community Forums
868: Community Forums
869: Home
870: Community Forums
871: Photo Gallery
872: Community Forums

Staff Online:

No staff members are online!
M1028 Canister Round for M1's at Ft Hood...
The AFV ASSOCIATION was formed in 1964 to support the thoughts and research of all those interested in Armored Fighting Vehicles and related topics, such as AFV drawings. The emphasis has always been on sharing information and communicating with other members of similar interests; e.g. German armor, Japanese AFVs, or whatever.
Post new topic    Reply to topic    Printer Friendly Page     Forum Index ›  AFV News Discussion Board

View previous topic :: View next topic  
Author Message
SFC_Jeff_Button
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 1311
Location: Ft Hood, TX
PostPosted: Sat Aug 19, 2006 1:55 am
Post subject: M1028 Canister Round for M1's at Ft Hood...

Todays Fort Hood Sentinal, (post paper) had an article that says the new M1028 Cannister round was fired for the first time this week at Ft Hood by 2nd Battalion, 5th Cavalry Regt. This round is a 120mm shell, and when fired, sends approximately 1,100, 3/8inch Tungsten steel balls down range. It creates a lethal barrage of pellets that travel at over 1,400 meters per second, OUCH! They compare it to a Claymore mine in its effect. I wonder what took so long to develop something like this? I envision a Mortar round that explodes downward with a smaller size pellet. Useing a proximity fuze it would leave virtually no square foot un-affected.

_________________
SFC Jeff Button "High Angle Hell"
Back to top
View user's profile Send e-mail Photo Gallery
Doug_Kibbey
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 4678
Location: The Great Satan
PostPosted: Sat Aug 19, 2006 2:38 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Those should give decent penetration against certain targets compared to our old canister round.

You'd have loved "can", Jeff...10,000 finned nails of love per round in a 152mm.
Back to top
View user's profile Visit poster's website Photo Gallery
SFC_Jeff_Button
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 1311
Location: Ft Hood, TX
PostPosted: Sat Aug 19, 2006 3:07 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Remember the "flechettes" I had from a 105 recoiless that I dug from a tree trunk at Ft Stewart that I showed you? This round reminded me of those. A nasty round to deal with. I'd love to see a huge paper target after its been shot by this new canister round.

_________________
SFC Jeff Button "High Angle Hell"
Back to top
View user's profile Send e-mail Photo Gallery
JimWeb
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 1439
Location: The back of beyond
PostPosted: Sat Aug 19, 2006 11:15 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

- SFC_Jeff_Button
I envision a Mortar round that explodes downward with a smaller size pellet.


They had them years ago - they were called shrapnel rounds. Abandoned in favour of HE.

Cool

_________________
TTFN
Jim

If your not a member of JED then your
not serious about anything military..

***********************
www.jedsite.info
JED Military Equipment
***********************
Back to top
View user's profile Visit poster's website ICQ Number
Roy_A_Lingle
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 1997
Location: El Paso & Ft Bliss, Texas
PostPosted: Sat Aug 19, 2006 3:59 pm
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Hi Jeff! Hi Folks!

- SFC_Jeff_Button

I wonder what took so long to develop something like this?


As I understand some of it:
1. the end user didn't see a need, the primary mission and the only mission for the Abrams was stopping a Warsaw Pact armored attack. This is why for a number of years, I saw the M1A1 as a Tank Destoryer and not as a Main Battle Tank.
2. with the upgrade to the 120mm cannon, the Abrams just doesn't have a lot of room for main gun rounds.
3. Back to point one, for the longest time, no body asked for a new canister round
4. Tank became a dirty word. Remember the term 'Legacy Forces'? The next war doesn't need a 70 ton monster which we can't get to a distance battle field.

It wasn't until the 8th Army gave up on the M728 CEV that they started asking for a new canister round for use in Korea. 8th Army kept the M728 CEV in it's units long after the state side Army stopped supporting the system. Current post 'Major Combat' actions in Iraq clearly showed there was a need or use for something beside the Sabot and MPAT rounds.

My take on why it took so long,
Sgt, Scouts Out! Smile

_________________
"You can never have too much reconnaissance."
General G.S. Patton Jr.
Back to top
View user's profile Send e-mail
Skeet
Power User

Offline Offline
Joined: May 15, 2006
Posts: 18

PostPosted: Tue Aug 22, 2006 7:15 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Wonder why they didn't use flechettes?

Wazza M728 CEV?
Back to top
View user's profile
Roy_A_Lingle
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 1997
Location: El Paso & Ft Bliss, Texas
PostPosted: Tue Aug 22, 2006 7:56 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Hi Skeet! Hi Folks!

- Skeet

Wonder why they didn't use flechettes?
Wazza M728 CEV?


Flechettes which are small nails work very well in heavy brush.
Steel balls work better in urban areas. Brick walls for one example.

M-728 CEV was a M-60 tank mounting a 165mm demolition howitzer, an A-frame for lifting things, a bull dozer blade with the fluid system mounted inside the armor rather than on the outside like a standard gun tank with a dozer blade.

CEV = Combat Engineer Vehicle

www.globalsecurity.org...d/m728.htm

My 2 cents and a spot report.
Sgt, Scouts Out!

_________________
"You can never have too much reconnaissance."
General G.S. Patton Jr.
Back to top
View user's profile Send e-mail
Skeet
Power User

Offline Offline
Joined: May 15, 2006
Posts: 18

PostPosted: Tue Aug 22, 2006 10:55 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Dang nab it Roy. I thought you knew. TY
Back to top
View user's profile
Doug_Kibbey
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 4678
Location: The Great Satan
PostPosted: Tue Aug 22, 2006 10:59 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

"Anatomy of an Abrams" aired last night on The Military Channel. I was surprized ot see it current enough to include the new canister round in it's section on main gun ammunition. I was really surprized, though, to see that the pellets were contained in the case where the propellent goes in the animated "x-ray view". Rolling Eyes
Back to top
View user's profile Visit poster's website Photo Gallery
Joe_D
Power User

Offline Offline
Joined: Jan 29, 2006
Posts: 2069
Location: Razorback Country
PostPosted: Tue Aug 22, 2006 11:14 am
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

Hi everyone,
I think we are getting our rounds and reasons mixed a little. The Cannister round was requested by 8th Army after we turned in our M1/105's for M1A1's in '95. We gave up the APERS (Bee Hive) with the change to 120mm. It had 5000 fletchettes and used a manual fuze that the loader set from MA (muzzel action) to 4400 meters. Fletchettes don't get that good of a dispersion pattern with a smoothbore since the round isn't spinning. So we got a shotgun shell on steroids. Cannister was developed to fill that need but was slow getting fielded until OIF experiences. My belief was because 2ID was the only folks that wanted it until then. The loss of the M728 (CEV) created a need for an obstacle reduction round. Again, 8th Army was asking for a round to fill that need. The answer was the HE-OR round (High Explosive-Obstacle Reduction) which is a modified MPAT. These actually were fielded in Korea prior to OIF. Hope this clears the picture a little.

Joe D
Back to top
View user's profile Photo Gallery
mike_Duplessis
Power User

Offline Offline
Joined: Jan 24, 2006
Posts: 236

PostPosted: Tue Aug 22, 2006 7:51 pm
Post subject: Re: M1028 Canister Round for M1's at Ft Hood...

I was under the understanding that flechettes had been banned under international treaty a long time ago (early 80s?). The wounds produced were just too nasty. I recall that same international convention sought to ban combat shotguns for the same reason, but the U.S. - pretty much the only user of combat shotguns anymore - dug in its heels and got its way. Remember, just a couple years ago there was a push to ban anti-personnel mines internationally but the U.S. dug in its heels once again. It main concern was covering the DMZ between N and S Korea without the use of anti-personnel mines.
Back to top
View user's profile
Display posts from previous:   
Post new topic    Reply to topic    Printer Friendly Page    Forum Index ›  AFV News Discussion Board
Page 1 of 1
All times are GMT - 6 Hours



Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum