204 need advise

[smitty55]

I have a 204 pac nor barrel 1-10 twist savage target action. here is the rub, last year I was loading 40 gr v max 25.5 gr 10x it was shooting lights out. Now I blow primers with that load, and down to 25.0 10 x . I have been at 24.8 shoots great again but WHY would the load change and blow primers. Same primers, cci 400 , same lot of bullets same seating depth .003 off lands and same powder. I have to leave this one to the more experienced I have tried to figure it out . Thanks

[skipper]

Were all the components of the same lot number. In other words, the same primers from the same lot number, same bullets from the same lot number, same powder from the same lot number? Something had to have changed. Ambient temperature, relative humidity, altitude?
The seating depth you stated has me scratching my head. In order to take an accurate measurement into the thousandths you would need an instrument capable of measuring to the tens of thousandths. You wrote .003. Did you intend to write .030?
I'm trying to help but I think more information is necessary.

[Rick in Oregon]

I've seen this before....the culprit? Copper fouling. The rifle was blowing primers too.

A friend's M700 22-250 did the same thing with the same proven load. I brought his rifle home, spent three evenings scrubbing the crap out of the barrel with CR-10, then more scrubbing with bronze brushes with Shooters Choice & Kroil 70/30 mix.

After that and getting down to bare metal, it shot cloverleaf groups just as before with his original load, normal appearing primers and launched rats way out there again.

Like Skpper mentioned....'what has changed?' Maybe the barrel has.......

[smitty55]

thanks guys for helping, same lot of primers, same lot of powder and bullets, I use a hornady measuring tool to find lands, and it shot 3 thousands off lands before one ragged hole . In three years from new barrel to now it has eroded three thousands, should not make any difference with load if nothing else it is 6 thousands off lands. At 25.5 it blows every primer. at 25.1 it blew one out of ten. at 24.8 shot fine. I clean barrel with sweets and scrub barrel no blue or anything when done clean patch. it just is boggling to me thanks again
JIm

[Jim White]

It could also be a carbon ring build up in the throat. It happens. Either way it has to be scrubbed out with time, cleaners and elbow grease. Not all cleaners are equal either. I use the same combo as Rick and it does a good job but on occasion, a little extra effort is required to get the carbon, copper and powder fouling completly cleaned out.

[TwentyBore]

Are you verifying your charge weight with check weights?

[smitty55]

I have a bar scale very accurate checked with friends weight right on. I even shot the loads that I had made up and used for groundhogs that worked fine. I am doing major clean today on barrel. sI always run carb out first before sweets scurb with brush , patch till clean, I give it some extra work scrubbing today

[skipper]

Once, a few years ago I was cleaning the barrel on my XR-100 and I left a patch wetted with Hoppes #9 bore cleaner on it in the forward throat area and went inside to get something. I ended up eating lunch and doing some other things before I returned hours later. On extraction, the patch was almost black. I had experienced the same thing that Jim White was referring to. A build up of burnt powder just forward of the throat. It had hardened to the consistency of ceramic tile!!! Try soaking that barrel with the bore cleaner of your choice and see if you may be experiencing the same phenomenon. Scrub, scrub, scrub before you do something drastic. Find a bore scope, if you can.

[smitty55]

I will try that it is soaking as we speak thanks

[Jim White]

SLIP 2000 is a good carbon cleaner but; it is water based so it must be completely removed, so don't leave it over night. But in the end, some good quality brushes and elbow grease is needed.

HTH,

[smitty55]

I soaked the barrel especially around throat. cleaned no black at all scrubbed with brush again still nothing.so off to range yesterday, old pet load blew primer, I have come to the conclusion that for what ever reason it will not handle this load anymore, shot new loads 1 grain less powder than the pet load, same col, shoots great. the new load shoots like pet load in the low 3s at 100, so it is what it is, it will haunt me WHY but it shoots where it is so be it!!! Thanks for all the info
Jim

[Bill K]

I have a 204 pac nor barrel 1-10 twist savage target action. here is the rub, last year I was loading 40 gr v max 25.5 gr 10x it was shooting lights out. Now I blow primers with that load, and down to 25.0 10 x . I have been at 24.8 shoots great again but WHY would the load change and blow primers. Same primers, cci 400 , same lot of bullets same seating depth .003 off lands and same powder. I have to leave this one to the more experienced I have tried to figure it out . Thanks

In reading this and the other post's, I may have missed it, but is the 10X you loaded the new/same loads with a different canister of powder, than you originally did ? If it is of a different lot number that could make just enough difference to raise pressure and cause pressure signs to start popping up, even tho you used this same load, bullet, etc. before. Just a thought and sorry to repeat if I missed that point. That could be why now you are one grain less and back to a good accurate load. Bill K

[smitty55]

thanks bill for info, I have a 7 lb jug of 10x same powder, it baffles me but I guess it is shooting so like they say don't fix what is working, but again drives me nuts I just have the need to know

[Jim White]

LOT #'s can make a difference; not only in powder but in primers and bullets too. WRT to cleaning, make sure it doesn't get to far behind the cleaning curve. I first heard of the carbon ring years ago from those that used moly and opted not to scrub there barrels clean very often, if at all.

Check & recheck your scales, frequently. last year I discovered my MECH scale went south even though it would pass the calibrated weight scale checks.

Good to hear it's shooting for you again.