Need help figuring this out

[artjr338wm]

At my last range session I experienced some never before oddities, that I THINK I know the cause but would like those here with more knowledge than my self to help determine if I am correct about what I think caused my problems.

To start with I found out while at the range prior to firing my first shot of the day, much to my utter disappointment that I had failed to clean my 10ML-II from my last range session where I fired between 25-27 shots. I, how ever, had thoroughly clean my breach plug and Lehi vent liner.

The anomaly and I experienced was for the very first time I suffered several blown sabots. By blown I mean shredded into pieces. These were the yellow factory supplied by Barnes sabots for use with their 245 grain Spitfires. With in a three shot group I would get two shots that would over lap, basically forming one hole and one would be off paper and I would then recover a shredded/blown sabot. The blown sabots I recovered were torn in to two equal sized pieces with two of the four petals still attached to each seperate sabot section and the flat bottom portion of the sabot where the bullets rests was intact and still attached to one of the sabot halves. I was using a iced down cooling rod so I strongly doubt the out side temp of 80-83* was a factor. I was using my usual heavy loads of 75grns of H-4198, but I have fired 100++ of these loads and never once do I recall suffering a sabot failure.

So through process of elimination the only thing that I know for certain that had changed or was different that could have caused my incidents of sabot failure was my quite dirty bore.

So my question is can a barrel badly fowled with plastic and powder deposits cause a high enough increase in pressure to cause sabots to fail?

One other condition I should mention is I did shoot some of my base line accuracy load (I do this any time I have accuracy issues to quickly determine or eliminate if shooter error is the cause) I know shoots 1.25 MOA or better and although I did not experience any sabot failure, I did have my groups open up to around 2-2.5" for a 3-shot 100yrd group. These shots were taken after my shot total between cleanings had well surpassed 35 shots.

If nothing else I have learned that the maximum shots I can fire between a complete barrel cleaning is no more than 25 shots.

So am I correct in blaming my blown sabots on a badly fowled bore as I suspect, or does anyone think I am missing some other cause?

Thanks,
Arthur.

[tdillinger]

the petals were off and the base was gone shredded? If so that is to much PSI i think. Im guessing the fowling escalated your demise at the range.

[dannoboone]

You're probably right, Art. In the beginning, I had a few sabot failures like that, too, even though
I dry swabbed between shots.

I'm not going to preach doing this because a lot of guys just plain do not want to do it, but
I've gone to partially wet patching between shots using Richard's method. Prior to that, I
was way overdoing it with a wet patch, needing two dry patches to dry the barrel. Four
small drops of Hoppe's #9 around the patched jag behind where it will make contact with
the BP, followed by one dry patch keeps the barrel in the same condition for each and
every shot.

I have not cleaned the barrel since early Spring, '09 and have
no idea how many shots have gone through it since. At the
range earlier this week the target was getting touching holes
after sighting in for a new load.

[artjr338wm]

I probubly should have also included I use the fallowing in-between shots cleaning method after every shot:

#1-using a .50 cal nylon bore brush I run a patch soaked in action cleaner up and down my bore 1x, flip and repete
#2-using the same nylon bore bush run a clean dry patch up and down 1x and discard.

[whyohe]

I had the same thing this year. my problem was i didnt bring my cleaning rod and didnt clean between shots like i use to do. I have a very tight bore and i think the dirty bore was causing some blown sabot and inaccuracy that i didnt have before.

as side thought do you think sabots can go "bad"? do you think as they get older they might get weeker?

[artjr338wm]

Thanks everyone for your feed back. Whyohe FWIW, I am a little puzzeled about my sabot failure as I have a bore that is a lttle on the loose side as I need red CRS to get the best fit with XTPs as oposed to using black CRS.

[mike3132]

I suspect it was heat, hot loads and a loose bore that caused the problem. If you have a loose bore and shoot 245 Spitfires read this. dougva.proboards.com/index.cgi?board=Savage&action=display&thread=1224

Once you melt sabots sometimes sabot fouling stays in the gun and causes accuracy problems. In the past Ive used J&B Bore cleaner for this and accuracy comes right back. Mike

[tar12]

It is a balancing act with these rough bores as some are worse than others. As a result you will need fouling in the bore for consistancy. It varies from gun to gun as to how many shots you can run before cleaning the barrel.There is a point of diminshing return in regards to accuracy.