Having recently wondered if my barrel was slightly oversized I was looking for a way to test the fit on some saboted .41cal or sabotless .458 bullets before shelling out the $$$ to buy them and risk having two expensive boxes of sinkers. I decided the easiest was would be to wrap some pieces of printer paper around a 40cal SST, measure with a micrometer and then try to get it down the barrel.
First of all I was surprised how much just a single layer affected the fit.
I started with two wraps and mic'ed it at .42. I didn't expect that much of a change but since it was already put together I decided to go for it and stuck it in a tan MMP sabot. No dice. I was able to push it just inside the crown before I decided there was no need to go any further. I stuck the range rod in the back and popped it out.
Next - I removed one of the wraps and this time it mic'ed around .406. It seemed the compression from the first test reduced the paper thickness. I tried again with the tan MMP and was able to push it all the way through with some effort. Still too much effort for a regular load and not really feasible since there aren't any .406 bullets out there that I know.
Last test was with the Harvester smooth blue. These things are much looser than the MMP and I had the idea of trying them with a .41cal XTP. I wrapped the bullet again with 2 pieces of the paper and this time they mic'ed at .412 which was consistent with what the single piece measured. I was able to get the load all the way through the barrel. It was easier than the MMP with one piece of paper by a slight margin and MAYBE easy enough to consider using.
I think this may have given me enough confidence to get a box of the 41cal XTPs and shoot them in the Harvester sabots. What I'm still skeptical about is whether or not the .458 bullet will fit sabotless. This would be ideal as it gives me more and better options. I suppose I could also bite the bullet (no pun intended) and get an adjustable sizing die to size the .458 down a couple thousandths. There's also the option of using a regular 200gr XTP in the MMP which apparently is a bit softer and will obturate more upon ignition but I'm not super confident in that bullet past 150 yards...and I guess that same level of confidence would extend to the 41 XTP. But why not experiment?
This may explain some of my barrel heat/flier issues. It's not a solution...but an explanation that may lead to one. We shall see.
First of all I was surprised how much just a single layer affected the fit.
I started with two wraps and mic'ed it at .42. I didn't expect that much of a change but since it was already put together I decided to go for it and stuck it in a tan MMP sabot. No dice. I was able to push it just inside the crown before I decided there was no need to go any further. I stuck the range rod in the back and popped it out.
Next - I removed one of the wraps and this time it mic'ed around .406. It seemed the compression from the first test reduced the paper thickness. I tried again with the tan MMP and was able to push it all the way through with some effort. Still too much effort for a regular load and not really feasible since there aren't any .406 bullets out there that I know.
Last test was with the Harvester smooth blue. These things are much looser than the MMP and I had the idea of trying them with a .41cal XTP. I wrapped the bullet again with 2 pieces of the paper and this time they mic'ed at .412 which was consistent with what the single piece measured. I was able to get the load all the way through the barrel. It was easier than the MMP with one piece of paper by a slight margin and MAYBE easy enough to consider using.
I think this may have given me enough confidence to get a box of the 41cal XTPs and shoot them in the Harvester sabots. What I'm still skeptical about is whether or not the .458 bullet will fit sabotless. This would be ideal as it gives me more and better options. I suppose I could also bite the bullet (no pun intended) and get an adjustable sizing die to size the .458 down a couple thousandths. There's also the option of using a regular 200gr XTP in the MMP which apparently is a bit softer and will obturate more upon ignition but I'm not super confident in that bullet past 150 yards...and I guess that same level of confidence would extend to the 41 XTP. But why not experiment?
This may explain some of my barrel heat/flier issues. It's not a solution...but an explanation that may lead to one. We shall see.
rayer:
