Im losing sleep because of this!!!

[Savageshooter12]

So I had a sweet load of 34gr of imr4064 with a 55gr vmax in my savage 12 22-250. WAS shooting half MOA all the way out to 300. Now it won't do it anymore. I mean the group has opened up 100-300 yards and I haven't changed anything. I tried a new load with different powder and bullets. Got awesome accuracy but nothing like I was getting with my vmax load. Barrel has low round count. Maybe 500-600 rounds. Not even a year old rifle. Any reason to why my load could have magically changed. I did devolve the load in the winter but I didn't think imr4064 was temp sensitive. Anybody think of any reason this could had happen. Any info will help. I'm becoming restless

[eddiesindian]

What were your speeds when you developed the load?

[keeki]

Copper?

[foxx]

I'd suspect the barrel is too dirty with carbon and/or copper
or
brass needs annealing
or
powder more temp sensitive than you think
or
powder different batch

[bigedp51]

Did you ever think you might have a few loose screws https://www.canadiangunnutz.com/forum/images/smilies/new/evil.gif
Bazinga and go ahead and get torqued off

Savage Action Screw Torque Tuning
http://www.accurateshooter.com/technical-articles/savage-action-screw-torque-tuning/

[hafejd30]

Imr 4064 is temp sensitive. I believe 1 fps per degree change on average (from what I remember) back the charge off .2 grains and see what it does

[Savageshooter12]

My next step was to increase or decrease charge. 34gr was the start charge. According to hogdon.

[Savageshooter12]

Around 3550-3600 for speed

[Savageshooter12]

Imr 4064 is temp sensitive. I believe 1 fps per degree change on average (from what I remember) back the charge off .2 grains and see what it does

Temp has maybe varied 25-30 degrees from devolpment.

[bigedp51]

Imr 4064 is temp sensitive. I believe 1 fps per degree change on average (from what I remember) back the charge off .2 grains and see what it does

The ammunition below was temp sensitive and loaded with RL15

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

The military switched to IMR-4064 a single base powder that is far less temp sensitive.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g)

Below double base powders are considered temp sensitive and the military selected IMR-4064 a single base powder.

http://i.imgur.com/33XPgx3.jpg

[foxx]

The worst case I have experienced with temp was RL-19 for 25-06. 50* change completely destroyed an exceptionally good load.

If it were me, I would play with powder charge and anneal the brass in case neck tension has changed. Possibly full length size if you normally only neck size.

[foxx]

The ammunition below was temp sensitive and loaded with RL15

Cartridge, Caliber 7.62mm, NATO, Ball, Special, M118LR (United States): 175-grain (11.3 g) 7.62×51mm NATO Match-grade round specifically designed for long-range sniping. It uses a 175-grain (11.3 g) Sierra Match King Hollow Point Boat Tail bullet. Produced at Lake City Army Ammunition Plant. The propellant's noticeable muzzle flash and temperature sensitivity led to the development of the MK 316 MOD 0 for Special Operations use.

The military switched to IMR-4064 a single base powder that is far less temp sensitive.

Cartridge, Caliber 7.62mm Special Ball, Long Range, MK 316 MOD 0 (United States): A 175-grain (11.3 g) round specifically designed for long-range sniping consisting of Sierra MatchKing Hollow Point Boat Tail projectiles, Federal Cartridge Company match cartridge cases and Gold Medal Match primers. The Propellant has been verified as IMR 4064 (per NSN 1305-01-567-6944 and Federal Cartridge Company Contract/Order Number N0016408DJN28 and has a charge weight per the specs of 41.745-grain (2.7 g)

Below double base powders are considered temp sensitive and the military selected IMR-4064 a single base powder.

http://i.imgur.com/33XPgx3.jpg

I don't know this for a fact, only repeating what I think I remember reading from credible sources... some powders are very INsensitive to temp change in CERTAIN cartridges, Change the bullet, or caliber, etc. and it's insensitivity is lost. Similarly, a very sensitive powder in one particular cartridge can be made almost INsensitive in a different application.

[bigedp51]

I don't know this for a fact, only repeating what I think I remember reading from credible sources... some powders are very INsensitive to temp change in CERTAIN cartridges, Change the bullet, or caliber, etc. and it's insensitivity is lost. Similarly, a very sensitive powder in one particular cartridge can be made almost INsensitive in a different application.

Powder temp sensitivity listed on chart above, temp stability is represented in fps/per degree Fahrenheit.

Example, RL15 1.52 fps per degree of temp change and IMR-4064 0.45 fps per degree of temp change. Single base powders are not considered as temp sensitive as double base powder due to nitroglycerin content and are more temp sensitive.

[Savageshooter12]

I developed a load for the 22-250 when I first got the gun. 36gr of varget with a 50gr nosler by. Shot very well in the winter. I tried it today and it still shot very well. I may just go back to varget since the load seem to work well then and now.

[lvjake7761]

my first thought was copper too and it's also not unheard for something have come loose
i'd start there before changing anything with your load

and even if your cleaning regularly unless you're specifically going after copper with something like sweets
it can build up to a point of hurting your accuracy

my hero Rex explains this very well in his sniper 101 videos this one Part 40 about coppering and powder fouling
https://www.youtube.com/watch?v=_KRUAv3Byp4&index=40&list=PLJUaiRIEduNXoal2_PkBZi0vDCIcEPxUn

this vid too
https://www.youtube.com/watch?v=GcmuSXqmKjs&list=PLJUaiRIEduNXoal2_PkBZi0vDCIcEPxUn&index=45



this might help

[m12lrs]

So I had a sweet load of 34gr of imr4064 with a 55gr vmax in my savage 12 22-250. WAS shooting half MOA all the way out to 300. Now it won't do it anymore. I mean the group has opened up 100-300 yards and I haven't changed anything. I tried a new load with different powder and bullets. Got awesome accuracy but nothing like I was getting with my vmax load. Barrel has low round count. Maybe 500-600 rounds. Not even a year old rifle. Any reason to why my load could have magically changed. I did devolve the load in the winter but I didn't think imr4064 was temp sensitive. Anybody think of any reason this could had happen. Any info will help. I'm becoming restless

Did you develop this load with new brass. Brass changes after fireforming. Loads developed with virgin brass never hold up.

[The Old Coach]

Copper?

Don't do nothin' until you've got the bore 100% decoppered.

[keeki]

Had a 243 do the same thing, turned out to be copper. Took 5-600 rounds before it went south, got the copper out and went right back to shooting bugholes

[darkker]

So I had a sweet load of 34gr of imr4064 with a 55gr vmax in my savage 12 22-250. WAS shooting half MOA all the way out to 300. Now it won't do it anymore. I mean the group has opened up 100-300 yards and I haven't changed anything. I tried a new load with different powder and bullets. Got awesome accuracy but nothing like I was getting with my vmax load. Barrel has low round count. Maybe 500-600 rounds. Not even a year old rifle. Any reason to why my load could have magically changed. I did devolve the load in the winter but I didn't think imr4064 was temp sensitive. Anybody think of any reason this could had happen. Any info will help. I'm becoming restless Listing a charge in grains but not listing the velocity, is like telling us you have a supermodel for a girlfriend, but can't show us because she had to leave for a while... Need to know how hot you ran that, and how fast you were shooting. We've burned out 22-250 barrels in 500 shots really easy over in Wy at a dogtown. So what changed? Well you realize that powders lots vary by 10% regularly, and if you were already shooting a very hot load, swapped to a new lot number that burned even faster by 10%.... Well, I'll let you do the math. Or are you buying German powder now? Hodgdon swapped suppliers yet again, so IMR-4064 is only a General Dynamics powder in the 1# bottles, and Rhinemetal in the 8# bottles. If you think Rhine is making the IDENTICAL powder as GD, you are fooling yourself.

[Deadshot2]

I developed a load for the 22-250 when I first got the gun. 36gr of varget with a 50gr nosler by. Shot very well in the winter. I tried it today and it still shot very well. I may just go back to varget since the load seem to work well then and now.

Considering that Varget has the lowest listed temp sensitivity factor in the linked chart that makes a strong case for you to just back down a little on your IMR 4064 a little. It will probably take only a few tenths of a grain so I wouldn't worry too much about getting into the "detonation zone". The "starting load" is considered to be one that creates enough pressure to obturate the bullet enough to get a good seal in the bore. If you aren't getting a bunch of soot down the side of the case, at least you are getting enough pressure to seal the case to the chamber and by assumption, enough pressure to seal the bullet in the bore.

Could be your rifle has a very narrow node around your selected charge weight and a higher node might be more "forgiving" of temp/speed variations.