I'm going to try a long range prarie dog tomorrow at a friends ranch so today I found a good load for my 6-284 using a 105 gr A-Max and 49 gr RL-22. It shot a five shot one hole group at 100 yds going 3265 fps with no pressure signs. This was using new sized Lapua brass so I shot another 5 shot group with twice fired brass. There were 2 shots touching and then the zinger, I had one keyhole about 1/2 inch left and a half inch low. This shot chrono'd at 3272 and the next two shots completed a group that was about .3 inch. I am far from an expert and these groups are very good for me. There have been about 30 of these bullets down the barrel with no problems and it seems to me that an unstable bullet wouldn't have been so close to the other shots. Was this a bullet failure that was just a fluke or what? Should I be concerned as I was hoping to use this bullet on whitetail this fall? My rifle is a CRF M 70 with a 30 inch ABS/Rock 1-8 twist. Any input would be helpful.
If it was just the one bullet that flew off target i probably wouldnt worry about it. The Amax is one of my favorite bullets but like any mass produced item there will be the occasional flaw. I also like the amax for a varmint bullet over alot of the berger or sierra bullets because the polymer tip ensures better expansion at low velocties than the other bullets tend to produce.
go shootin and have fun
take it easy
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Re: A-Max problem?
Is there ANY chance that bullet could have hit a blade of grass, twig or any other object?? It does not take much to get a bullet sideways. If there was no chance, it could have been one defective bullet. I wouldnt worry too much.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.
You will find my friend that in most cases, a 6-284 with a 1-8 twist will be limited to around 3250 to 3300 fps with the 105 gr A-Max.
I would be currious to see how wide the lands are on that Rock barrel. I got one of Mikes 7mm barrels for my 7mm AM to shoot the 200 gr ULD RBBTs as the Lilja 3 groove barrels were tearing them apart after a few hundred rounds or less in some cases.
Well, right from the start the Rock was tearing bullets apart at any velocity. The reason, to much bullet baring surface compression.
Called up Rock Barrels, their main barrel maker worked with me, thinned the lands and now their bullets work perfectly.
I would suspect this is a similiar problem as you are seeing.
You are just not tearing them apart but if the jacket core bond is weakened, accuracy will suffer ranging from poor groups to total bullet failure in flight.
Since this was just one bullet, I would not worry to much about it but pay attention. If those bullets seem to not make it to target like they should, make a mental note.
Good news, you can always use the 107 gr SMK as it will take alot more velocity before loosing accuracy.
My personal 6-284 will get 3550 fps with the 105 gr A-Max. Only problem is that anything over 3250 fps will cause accuracy to go to hell instantly, same with the Berger 105 gr VLDs. THe SMK can be driven to 3550 with fine accuracy all the way up with its thicker jacket.
Anyway, just something to be aware of. If your getting more then around 25% baring surface compression on your bullets from the lands, you may be having this problem and I suspect your well over that if the 6mm Rock barrels are similiar to the original 7mm Rock 5R barrels.
Again, just pay attention when your shooting. May be a one time deal, may not. Time will tell.
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The 107 gr SMK's shoot very well in my rifle with about any reasonable load, they just don't perform on deer way out there. I was hoping the A-Max would work better as some people have indicated it would. The accuracy and velocity is fine with me, I just don't need a bullet going goofy at the wrong time. I loaded some 87 gr V-Max and got I think 3700 fps but it was good then bad on the consistency. It's time to stop working on paper and try some fur. We'll see what happens tomorrow and I have some 105 gr Berger and some 110 gr Wildcat that may work better but there has been quite a bit of powder burnt on some mediocre results.