usmc1974 Posted December 23, 2012 Share Posted December 23, 2012 I was told the the 175 bthp bullet will break the operating rod on M1A rifles. Is this possable? Link to comment Share on other sites More sharing options...
JimmyZip Posted December 23, 2012 Share Posted December 23, 2012 Very interested to hear how a bullet will break an op rod. Link to comment Share on other sites More sharing options...
mike4045 Posted December 23, 2012 Share Posted December 23, 2012 Not sure about that. I shoot 150gr factory ammo and 168 gr for longer range work. I am thinking of trying 175 in my bolt gun. It really does like the 155 sierra palma bullets. Mike Link to comment Share on other sites More sharing options...
ShootfastRunfaster Posted December 24, 2012 Share Posted December 24, 2012 Someone out there is spinning a tall one. I have not had any problem with 175's in mine. Don't forget that original M118 is loaded with a 173 gr fmj and has been used that way for decades. I'm sure if there was a problem shooting a bullet weight in that range it would have popped up a long time ago. M118 LR uses the Sierra 175 and I have yet to see it take a rifle apart. Kuan Link to comment Share on other sites More sharing options...
HRider Posted December 24, 2012 Share Posted December 24, 2012 I have not heard of problems with M1As. I have heard of Garands bending the oprod and splitting stocks as a result of overpressure from heavy bullets or different burn rates of powder from the original design. That said, I believe even the old Government match load for 30'06 was 175gr, the CMP says not to use bullets heavier than 180 gr in M1 Garands. Hurley Link to comment Share on other sites More sharing options...
JimmyZip Posted December 24, 2012 Share Posted December 24, 2012 I have not heard of problems with M1As. I have heard of Garands bending the oprod and splitting stocks as a result of overpressure from heavy bullets or different burn rates of powder from the original design. That said, I believe even the old Government match load for 30'06 was 175gr, the CMP says not to use bullets heavier than 180 gr in M1 Garands. Hurley Wow! so even if not this rifle, some rifles can have a issue with heavier projectiles causing over gassing resulting in operating rod damage? Wow, good thing to be aware of. Link to comment Share on other sites More sharing options...
Dan Sierpina Posted December 24, 2012 Share Posted December 24, 2012 Wow! so even if not this rifle, some rifles can have a issue with heavier projectiles causing over gassing resulting in operating rod damage? Wow, good thing to be aware of. I was told years ago, not to use any powder slower than 4064 in a Garand. The slower powders change the pressure curve and will bend the long M1 Op Rod. Link to comment Share on other sites More sharing options...
redial Posted December 24, 2012 Share Posted December 24, 2012 usmc, Like others have said, your pressure curves have to stay within (or close to) the design parameters. Using 175s or any other bullet won't harm the rifle IF matched with an appropriate powder and charge. Trying to shoot 190 or 200 Sierras over a huge charge of WW760 or IMR4350 damaged some rifles a decade or three ago. Some have resorted to vented gas plugs for certain applications. 175s with IMR4064 works great. When I finally retired my .30 cals, I shot that combo at all stages from 200 to 1,000 yards. Mark Link to comment Share on other sites More sharing options...
usmc1974 Posted December 24, 2012 Author Share Posted December 24, 2012 (edited) Wow! so even if not this rifle, some rifles can have a issue with heavier projectiles causing over gassing resulting in operating rod damage? Wow, good thing to be aware of. I was told years ago, not to use any powder slower than 4064 in a Garand. The slower powders change the pressure curve and will bend the long M1 Op Rod. I did not know this. Edited December 24, 2012 by usmc1974 Link to comment Share on other sites More sharing options...
Langenator Posted December 24, 2012 Share Posted December 24, 2012 Wow! so even if not this rifle, some rifles can have a issue with heavier projectiles causing over gassing resulting in operating rod damage? Wow, good thing to be aware of. I was told years ago, not to use any powder slower than 4064 in a Garand. The slower powders change the pressure curve and will bend the long M1 Op Rod. I did not know this. If you want to read some really involved discussions on this topic, wander over to the CMP forums. That's where the SMEs on this particular rabbit hole live. I found one thread that spanned over 10 pages and several years when I was looking up ammo for my M1 prior to shooting WWII division at LaRue last April. Link to comment Share on other sites More sharing options...
paul gilman Posted December 25, 2012 Share Posted December 25, 2012 You can use the 175 gr. bullets in the M14/M1A, you have to use powders in the range of 4895, with 4064 being the slowest. 4895 is the go to powder for this gun with match bullets to start. what happens is if you use to slow of a powder the pressure goes to high latter in the firing processe and cause to much stress on the op rod. the are gas plugs that will bleed of the pressure spikes, I would still not use any powders that are slower than 4064. Link to comment Share on other sites More sharing options...
Shooting Coach Posted February 9, 2015 Share Posted February 9, 2015 The M118LR WILL damage the Op Rod on a standard M1-A. If you want to use bullets over 168 gr bullets, and shoot small groups over a long period of time with your M1-A, get a Sadlak grooved NM piston. The piston is a lot cheaper than a new Operating Rod. Less than $60 shipped at Amazon. Link to comment Share on other sites More sharing options...
kurtm Posted February 9, 2015 Share Posted February 9, 2015 The above is a great example of none of the reasons Sadlak groves their "N.M." pistons. 175s are just fine in M14 rifles. The gas system is pretty well " self regulating" without any groove. The grove merely allows a small amount of gas to be directed to the front of the piston a bit sooner than going into the piston hole and then going forward to the cap and starting rearward thrust. The piston, theoretically moves a bit smoother and a more consistent thrust on the op rod face. All well and good, but it is much more critical to center the op rod to the piston for longevity than ha ing a wonder grove cut in the top of the piston. Side note: New M1As have a resistance welded TWO PIECE guide rod assembly that is NO WHERE NEAR G.I. Spec which was a one piece forging. The good news is they don't bend....they break. I have seen several break now, mainly on the shorter barrel M1As, but I have seen one rifle length one break. I have never seen a G.I. M14 op rod bend....ever, and as someone rightly pointed out the original XM 118 and M118 ball was loaded with a 173 grain bullet and it wasn't a light load! I have seen pallets worth of that shot out of M-14s and not one single bent op rod. I have seen worn out op rods where the caming surface is peened out and the receiver guide tab looks like a razor blade......but still straight. Side note 2. Unless you really know what you are doing, and how to do it, if you want your op rod centered to your piston it is best to send it to someone who really knows how to build a match grade M14. It is akin to straightening a crank shaft in a V-8. Link to comment Share on other sites More sharing options...
dauntedfuture Posted February 9, 2015 Share Posted February 9, 2015 In general you should not shoot bullets heavier then 180g with hot loads in an M14. the reason is that you can crack the receivers on the rifle and yes it does happen. Most of the service rifle teams shot hot OLD sierra 180g bullets in M14's. A few of them did wear out and or crack. These loads were reserved for the 1K line only and not shot across the course. I believe it was a stout load of IMR 4064 in a LC case. This was years ago, the 180g BTHP was modified and or discontinued at some point. A vented "piston cap thing" I think its called.... will vent some of the gas and make a softer shooting rifle, in general the M14 is over gassed anyway. The porting also has a more noticeable effect in that you brass does not stretch as much. In a M1 Garand you should use care and use power in the 4895 to 4064 range. This in the correct general old guidance. It is still true, but as not all that many shooters shoot M1's any more, there has not been as much data with Varget and the like. I know IMR 3031 works as well. In a Garand you should limit bullets to 147-190. The danger is that you can bend the OP rod in the rifle. the rifle will still function fine, BUT a big part of tuning a NM M1 is to properly bend the op rod. I don't know how to do this but its a real thing that is done so that while in recoil the rod does not connect w. the stock. If you run powder too slow you can bend the OP rod in a way as to "sour the accuracy" Back in the day when a NM M1 went "sour" this was a common thing to check and or replace. In general with a M1 you are best to stick with surplus ammo or special handloads. I think that federal and Hornady now make ammo special for the M1 with the correct burning rate powder. Shooting hunting ammo in an M1 can damage it. Link to comment Share on other sites More sharing options...
kurtm Posted February 9, 2015 Share Posted February 9, 2015 (edited) A lot of cross pollonization going on in this thread. Yes some M-14 receivers did crack, it kind of followed manufacturers...an H&R might, a Winchester might, a TRW cracking would be very rare indeed. It had nothing to do with bullet weight. Vented end caps were indeed utilized....in M1 Garands in the civilian market as a " tuning" trick, and to use heavier bullets, but not for the M-14. The M-14 isn't over gased, it is a vented short stroke piston system. If indeed you got hotter ammo the piston would indeed move back faster, but it also vented faster making it a wash. It is a great gas system as it functions in a wide range of pressures and weights. M-14 operating rods don't bend! M1 Garand op rods will! Made worse by heavy bullets, ( more to follow) and mis matched powder, but it is a long stroke piston system and in no way similar to the M-14 gas system. Both rifles benefit greatly from centering the op rod, on the M-14 it gives a consistent thrust on bolt opening, on the Garand it help to first decrees drag and side loading on the piston head, and it prevents accuracy robbing vibrations by not contacting the front handguard ferrul/ op rod guide. M1s can shoot heavier bullets when loaded with the propper range of powder, this old caveat came from guys putting factory loaded180 grain hunting ammunition in their Garands. Back in the day these were loaded with very slow powders for use in bolt guns which did indeed damage some Garands and cause the op rods to bend and dissassemble from the receiver while firing. 175 grain bullets are just fine in the M-1A/ M-14. Using Garand specific ammo if you don't reload with the propper bullets and powder is great advice! Edited February 9, 2015 by kurtm Link to comment Share on other sites More sharing options...
Long Range Posted February 19, 2015 Share Posted February 19, 2015 Good (I think) reloading article for the M14 http://www.zediker.com/downloads/14_loading.pdf Link to comment Share on other sites More sharing options...
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