SmallCaliberCentral

Need advice again...I developed a load late last spring, early summer that shot very well, alot of 5shot groups under half inch. Didn't shoot much through summer and fall. Been keeping it with me in the truck now the last few weeks and have nailed some nice long shots at crows and other vermin, but started missing some I definitely should have hit. Put it to paper yesterday and it wouldn't group very well. Over an inch at 100. It's been maybe 75rounds since cleaning. Do you guys start losing some accuracy after that many rounds between cleanings? I had to wonder also if it has anything to do with developing the load in spring/summer heat and now it's cold (15-20) I'm sure the pressure is lower and velocity lower, if this changed how my gun likes the load? Running 39blitzes and RL10x. Going to clean it thoroughly today and c what I got. Fingers crossed that's all it is.

Could be that it does in fact need cleaning. Or since you keep it in your truck, etc. could you have damaged the crown, just enough to cause it the be off ? I would check both and go from there. Bill K

High intensity cartridges such as the 204R really should be cleaned after about 30 rounds downrange. Many folks do it after as few as 25 rounds.

When we're out shooting PD's or ground squirrels and fire upwards of 300+ rounds a day, cleaning after 30-50 rounds is a true PITA, but it keeps accuracy honed and does not let the carbon or copper build up. If the carbon is allowed to build, it can raise chamber pressures dramatically, and can actually get harder than the barrel steel. Removing it is a real chore that you'll not soon forget.

Copper, if allowed to build up can actually cause blown primers, as it reduces the I.D. of the bore and raise pressures to a dangerous degree. Seen it happen. Not saying this is your problem, but be aware of the shortcomings of not cleaning on a regular basis. 75 rounds through a 204R without cleaning is really pushing it.

Thank you both for the timely replies! I should have waited untill after cleaning and re-shooting to post...After cleaning it very well I fired a fouler and the next 4 shots were touching, the 5th was about a half inch off the group, I'll call it shooter error, that's what usually happens when i stack 4, have to ruin an awesome group with that last one . But no doubt a totally different gun from the group's I shot yesterday that were scattered. When doing all my load development I was cleaning between each trip to my bench so each load had the same opportunity. Note to myself I'll just need to clean oftener. And as for damaging the crown, it stays in a nice padded zippered case at all times when not stuck out the window when in the truck, I don't just let it bounce around the floor board

Glad you found the problem.. A clean bore is a sweet thing.. And glad you do watch the crown, so many do not. Bill K

I was doing some bench shooting with my Tikka .204 a few weeks ago and was doing fine for about 25-30 rounds. Could only shoot 5 or 6 before letting the barrel cool down a bit but all in all things were fine and groups were tight. Then it just started going all over the paper, granted a little breeze kicked up as it usually does in the high desert around Susanville but I figured I was just getting tired and the eyes weren't focusing as well. I got home and started to clean the barrel and found it took almost 30 patches to remove all the copper from the barrel. I haven't had it back out since but hope it was a fouled barrel that caused the problem. Thanks for the post-I think it clears up my problem.

I've got a Rem 700 204 that needs a cleaning every 50 or 75 rds in order to stay accurate. My JP barrel goes 200+ and very slowly loses accuracy beyond that. I've shot it 700 rds without copper cleaning the barrel and it still grouped my loads under 1.1"... which is all I ask of it. The only caveat I have is that I don't push the bullets past 3,600 fps. Both have very tight chambers, so I clean those after every outing.
$.02.