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Milsurp OAL vs SAAMI OAL |
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Sawbones 
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 Topic: Milsurp OAL vs SAAMI OALPosted: May 20 2022 at 11:48am |
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SAAMI = Sporting Arms and Manufacturing Institute Had the opportunity to Chrony some milsurp ammo to compare w/ reloaded 30 carbine ammo of a fellow Forum comrade. The reloaded ammo OALs were all 1.672"-1.675" and every one of the rounds jammed when chambering; tip of projectile hanging up on the rim mouth of the chamber. Curiously the milsurp stuff, namely Evansville Cartridge Company 1944 and Lake City 1952 all measured 1.665 +/- 0.002" all chambering beautifully w/o 1 jam. Likewise the off-the-shelf Sellier & Bellot ammo OALs measuring identically to that of the milsurp. Observation: SAAMI recommended OAL for the 30 carbine cartridge is 1.680". Milsurp obviously much shorter at 1.665" +/- 0.002". My carbine will not chamber any cartridge OAL > 1.670" Seems reasonable to me the shorter OAL of the milSURP ammo is in reality the actual milSPEC (military specification) for the USGI carbine and the longer SAAMI OAL spec is standard for the currently manufactured non-USGI commercial 30cal carbines. Make sense? Perhaps if some of you are having chambering issues w/ longer OAL ammo you might consider a shorter cartridge. I can see where some of you may be rolling your eyes thinking "Where did this moron roll off the cabbage truck" but this is quite a revelation to me, solves my chambering issues so I felt compelled to relay this to other folks on the Forum.
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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W5USMC
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Posted: May 20 2022 at 12:02pm |
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SAAMI= Sporting Arms and Ammunition Manufacturers' Institute
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Wayne
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floydthecat
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Posted: May 20 2022 at 12:08pm |
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Not that unusual to hear about carbines with chambering issues using some ammo. There was a change in chamber dimensions early on, which likely contributes to the issue as well as varying bullet profiles. Sometimes SAAMI specifications can seem like a suggestion.
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Sawbones
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Posted: May 20 2022 at 12:49pm |
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Floydthecat again I agree w/ you. The 1.680" OAL is the MAXIMUM OAL for the 30 carbine. I suspect anything longer may allow the bullet to encroach into the lands which causes other problems. To clarify: The SAAMI 1.680" OAL is not the standard OAL" for the 30 carbine cartridge; just don't go longer than 1.680". Trial and error OALs for your carbine to determine which OAL it likes. I'd begin at < 1.670". Again, all the 30cal milsurp I've measured was 1.665 +/- 0.002". All chambered beautifully in my USGI carbine. Incidentally: The Evansville 1944 WWII vintage ammo Chrony'd at 1,954, 1,931, 1,921 and1,925 feet/second which is a pretty tight range for any ammo. The Lake City 1952 Chrony'd at 1,963, 1,967, 1,929, 1,957 and 1,971 feet/second which is pretty tight. The Sellier & Ballott Chrony'd at 2,045, 2006, and 2,071 Which is pretty crappy when compared to milsurp.
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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Matt_X
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Posted: May 20 2022 at 1:07pm |
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Thank you! I for one really appreciate the velocities on both the historical and current ammo. How far out was the chronograph? |
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floydthecat
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Posted: May 20 2022 at 1:14pm |
Expand a bit on why you consider the S&B crappy? It’s faster than the other stuff you tested. I shoot a lot of S&B in several calibers and in every case, it is hotter stuff. The 9mm is consistently warm at around 1260fps on average. Military grade stuff runs closer to 1300fps, but the S&B is right up there with it. I have never shot any 30-carbine S&B though. I just find S&B ammo to be warmer in the calibers I shoot it in and it’s not rated +p.
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Sawbones
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Posted: May 20 2022 at 1:45pm |
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Matt: Chrony was 8 feet from muzzle
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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Rebel92
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Posted: May 20 2022 at 2:09pm |
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Awesome information. It’s amazing that ammo that old still shoots like it did yesterday! Thanks for sharing!
I for sure have one carbine that I am only able to shoot mil surp ammo out of, and i bet it’s because it doesn’t like the longer profiles of most commercial ammo or the fatter projectiles in the Armscor
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Sawbones
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Posted: May 20 2022 at 2:21pm |
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Floydthecat: I am sorry my statement inferred Sollier & Ballott ammo is crappy, or inferior. I simply stated the wide range of velocities of of the Sellier & Bellott (65f/) is crappy when compared to that of the milsurp Evansville 1944 (33f/s) ammo and Lake City (42f/s). It was an opinion derived from decades of competition reloading and shooting. Velocity is a function of pressures.. The wide variance of velocities adversely affects downrange accuracy. Hotter loads does not necessarily bestow better accuracy. Frankly, I am satisfied w/ S & B ammo but if I were going to a 30 carbine competition shoot by all means gimme a coupla bandoliers of Evansville 1944!
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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Matt_X
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Posted: May 20 2022 at 2:22pm |
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Thanks. I figured it was prety to close to muzzle, but its always good to check. Some place I recently read an explanation of why the military velocities WW2 era were much further out. It had to do with the method of measuring velocity - which if I recall correctly involved high speed photography but in any case required the breaking of two planes at a given distance apart. Anyways its interesting to have some performance data of WW2 ammo to compare with using the same type of testing. FWIW, obviously a different chronograph and location, the S&B velocities measued by -Steve- in 2009 had a spread of 44 fps over 10 rounds. Posted here: https://forums.thecmp.org/showthread.php?t=2967 item 8) |
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Sawbones
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Posted: May 20 2022 at 2:34pm |
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I for sure have one carbine that I am only able to shoot mil surp ammo
out of, and i bet it’s because it doesn’t like the longer profiles of
most commercial ammo or the fatter projectiles in the Armscor Hey Rebel, I agree. Ya might seat that stuff down to ~1.665 and see what. Might remedy your dilemna
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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Rebel92
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Posted: May 20 2022 at 2:43pm |
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Floyd, what is “+P”
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Sawbones
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Posted: May 20 2022 at 3:01pm |
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FWIW, obviously a different chronograph and location, the S&B
velocities measued by -Steve- in 2009 had a spread of 44 fps over 10
rounds. Posted here: https://forums.thecmp.org/showthread.php?t=2967 item 8) Hey Matt: I went on the above thread. A very comprehensive treatise on the 30 Carbine! Covers everything one would need/want to know. I recommend it to all Forum folks.
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You can't fool all of the people all of the time.....but it isn't necessary. Will Rogers
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Smokpole
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Posted: May 20 2022 at 4:39pm |
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+P is a higher pressure ammo used in more strongly built firearms. It delivers higher pressures and higher velocities than regular ammo and isn't considered to be safe in many older firearms.
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floydthecat
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Posted: May 20 2022 at 6:36pm |
Of course that’s true. + designates an overpressure round. I only mentioned S&B because it is strong ammo, but not labeled as +p. I suspect some stuff labeled +p is not as strong as SB9A.
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Smokpole
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Posted: May 20 2022 at 8:38pm |
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With some of the current powders, it is possible to deliver higher speeds with the same amount of pressure delivered over a longer barrel burn time with slightly slower burning powders like AA9 for example. Case capacity limits the amount of powder, but burn rates can alter the pressure curves quite a bit. I've recently loaded a batch of 115 gr bullets with safe charges of AA9 but haven't had a chance to chronograph the loads yet. I do expect higher than normal velocity, but no increase in pressure signs.
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floydthecat
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Posted: May 21 2022 at 7:15am |
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I have never used any AA9, but Hodgdon says H108 is the same as AA9. I load H108 based on AA9 load data and it is a super good powder to handle. Nothing else I have meters and handles as well. I load 13-grains under a 110-grain bullet and have been completely satisfied. I have tested AA7 and it does work, but is a bit faster, yet about the slowest powder you can use in 9mm. I don’t use AA7 routinely, but noticed no ill effects from the few loads I tested. I might use AA7 in carbine loads when I can’t find anything else and I loaded it a bit lighter than H108/AA9. Cycles fine, brass and primers from fired cases looked just fine…no overpressure signs.
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David Milisock
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Posted: May 21 2022 at 8:50am |
I agree, Lil'Gun fills to case, burns slow enough for good velocities, works the action but does not over work it. To me it seems to burn cool, measures easily and works. Word of warning, Lil'Gun should be kept to 45,000 PSI or less, use in higher pressure cartridges has lead to excessive flame temperatures, enough to damage forcing cones.
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David Milisock
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Matt_X
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Posted: May 21 2022 at 1:10pm |
Remington Arms Co. Product Drawing C-30124 Feb 7, 1942 1.680" maximum, 1.660 ? " minimum In pencil next to that looks like 1.679" ? max and 1.637"? min. Possibly these pencil notes are for production engineering?? Drawing is in Riesch 8th edition, p188. Unfortunately digitized printing makes it near impossible to read under10x magnification. Kuhnhausen in figure 30 (p.44) provides the overall length as 1.680 max, but 1.625 min. for commercial. In note 1 he states the 1.625 minumum accounts for various bullet lengths, but it would be a 1.678" minumum "based on a seated 200955 standard military bullet." Phrased that way, I was not sure this 1.678" is actually on a the 1942 and 1943 drawings. Ruth's War Waby! vol II has a copy of Ordnance drawing B200954 for Ball Cartridge, revision 5 (10-3-1944). Overall length is 1.68 with a tolerance of -.02" By my math that's a minimum on inspection of 1.66"  Edited by Matt_X - May 21 2022 at 1:39pm |
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floydthecat
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Posted: May 21 2022 at 1:28pm |
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I do shoot 85-grain Mauser bullets seated to around 1.625. Hornady has a published load for it.
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Sawbones wrote: