This morning i planned to go fishing, but it was -3. Also, i was curious to see if the old diesel, loaded with all my shooting paraphernalia, would start. He was just fitted with a whole new set of glow plugs. Well, i moved the rifle, powder, and a clean target from the shop to the truck. The original plan was to go fishing, so the truck wasn't plugged in. Happily, he started right up, and after the windshield defrosted, we headed for the hills.

The load was 110g Blackhorn, 300g Deep Curl, crush rib sabot, CCI 250 primer. The rifle was the Dream Season. The range was 200 yard. The temperature through the shooting, was right at zero. In the beginning, the air was moving which i could feel, and it also moved my breath different directions. However, the moving air wasn't really a breeze, just gentle moving air. The first two shots were some high. The first was from a cold clean barrel. The second shot was from a barrel with one shot through it. The loading pressure using the crush rib sabot wasn't much, but seemed it was "enough".









However, when i loaded the third shot, i felt very very little resistance whilst shoving the bullet 'home'. The large change is loading resistance was very noticeable, and actually kinda surprising. This third shot went a way lower than the first two. The fourth shot loaded very easy, just like the third. The fifth shot loaded the same as the third, and the fourth. These easy loading shots made me wonder if i shouldn't be using a more tighter sabot, but they sure all hit in the same area, albeit, a lot lower than the first two shots.









What i wonder/wondered is if the bore expanded because it warmed, or if the Blackhorn residue acted as a 'lubricant', or both. At any rate the 'loose' load sure made for a different point of impact, and the force to put the bullet on the powder didn't seem it was enough.

Then a swirly breeze came, and i knew there was no use to shoot any more, but i did shoot twice more. The smoke from the sixth shot blew straight left, and that is where the bullet hit--a way left. The smoke from the seventh shot blew to the right.









Then i went home; then i went fishing. It warmed up real nice--36 degrees. All i caught was 2 itty bitty perch, about the size of a goldfish.

Very interesting range results there. Not shooting long distance this fascinates me. Perhaps a thicker sabot might be in order. It would be interesting to see the results on a similar morning. And nice shooting there.

Ron,

You don't suppose that the plastic sabots contracted or shrunk somewhat due to the extreme cold? It stands to reason that it could very well be the cause. Softer materials expand and contract more significantly due to temperature extremes. Try measuring the base of one of your sabots at room temperature (with a good quality micrometer or vernier caliper) and write down your reading. Then put it in the freezer overnight. Take it out the next day, wipe off any frost with a dry towel and DON'T handle it with your bare hands any more than you have to...and check it again. The extreme cold temps you were shooting under may have caused the sabots to shrink enough to where they seemed loose or easier loading than they normally would.

BPS

Trying another sabot under similar conditions may be informative . . . maybe the slightly thicker Harvester EZ.

I've found that the Harvester "Crush Rib" and "EZ" are not interchangable. And, for the loads I use, their application is counter intuitive. The Crush Rib works best with slightly smaller, .429" bullets, like the Deep Curl, while the EZ works best with larger, .430" XTP's. It seems like it would be the other way. Go figure. It leaves me guessing.

cayugad, Blackpowdersmoke, Bill308,

Thank you all for your advice.

Next time out i will try the short black Harvester sabot, and keep all else the same. Hopefully this will be instructional.

Well I have learned a ton from you and your long range shooting. It almost makes me think I could do the same. And this summer I do intend to try some of the things your doing.

One other thing you might think about... As someone has already mentioned the 'ambient air temp' and the effects on the sabot.

I will just mention what I have found with no scientific facts.

For myself and in my case most of my hunting is in the cold temps that you refer to. The polymer formulation used in Harvester sabots gets very hard and looses some of its pliability. I have always felt that because of this the sabot does not really mold itself to the lands and grooves of the barrel. This same theory helps me explain why Harvesters appear to work better in the warm temperatures or in a warm barrel, when the Harvester is able to mold itself to the bore.

On the other hand I have found that the polymer formulation use be MMP works very well in really cold temperatures and because it maintains pliability it does mold itself to the bore.

One of the reason that I believe this other than experiences is loading a snug harvester or a snug MMP in sub zero weather. Often the Harvester will be shaved slightly as it goes through the crown and the MMP NORMALLY does not. And I would suggest the MMP is easier to load all the way down the bore than is the Harvester.

On the warm end of the spectrum the MMP gets very gummy in warm weather or in a hot barrel. Gummy is probably not the right word in that it does not stick to the bore - it just becomes very soft in the presence of abnormal heat.

Just sharing..

I would have initially thought the sabot/bullet too. But with the 5th and 6th shots shooting only slightly lower than 1 and 2 I would have to think the lower shots were due to barrel expansion.
My reasoning is 1 & 2 were high. Quickly followed by 3 & 4 which by this time would have warmed up the barrel making a large difference in barrel temp and sabot/bullet. The only thing I don't know to confirm my theory is how long after #4 was 5 & 6 fired.

All the shots were loaded and fired about as quickly as an old person can move.

This morning it was -3 at the house. The old boy must have wanted to go for a ride; he started once again, without having been plugged in.

The Dream Season, powder, bullets, sabot, and primers spent the night in the much warmer shop. They were loaded up, and we headed out to 4700'. It was snowing like the dickens up there, and it was -8, but we were there, so we set out the target, and loaded the rifle.











Oops, it couldn't shoot. After cleaning it the last time, i put the wrong breech plug in the rifle. Couldn't shoot it. So..with the powder and bullet in place the breech plug was removed, and replaced with the plug that would shoot the large rifle primers. Some powder came out with the original plug, and some powder could be felt in the threads, and between the nose of the plug, and the barrel. The plug was tightened as tight as i could using a 1/4" ratchet, and some powder grains were smushed.. Well, i knew the first shot from the cold clean barrel was compromised, but what could i do but proceed. The shots are identified in the order they were taken. No wait time was taken between shots.













Snow doesn't seem to affect the bullets much. The snow was so heavy whilst taking shots 1, 2, and 3, i could barely see them holes through the spotting scope. Then the snow let up, and the target was more easy to see. However, the tape wanted to obscure the holes made by 4, and 5, because it was curling away from the cardboard. When the trigger was pulled for shot 6, a nasty gust of wind happened right then, and the smoke blew quite strongly left, and away.

Group 2,3,4,5,7, 8 measures 3 1/4".

Group 3,4,5,7,8 measures 2 3/8".

Group 4, 5, 7, 8 measures 1 1/4".


It does seem the use of the tighter sabot did tend to keep the first shots closer to the later shots. However, the load for the first shot was different than the load for the rest, and this means more, and more shooting is required, so for to see where the very first shot from a cold clean barrel will impact.