velocity questions

[dirtboy]

I shot my rem/Pac 45 last weekend to check velocities so i could order my CDS dial from leupold to try that out but had a few questions first. It was around 65 degrees and I was shooting 61gr. 4198 and 200sst lightly knurled out of a dirty barrel that had been shot 7 days before this session. First shot 2835 second shot 2685. Third shot 2560 I only had 3 knurled 200sst so i had 3 195 Barnes ex knurled and i shoot this with 62gr. 4198 and the three shots were 2550-2580. Just wondering if this is normal out of a dirty barrel for the first shot to be that high. I cleaned it and plan on shooting 3 shots this weekend with the chronograph up to check a clean barrel. Thanks

[jims]

I cannot recall having that much variation in speed on a clean barrel versus a fouled one. What I have found more is that there may be some difference in POI but generally it was more right to left than vertical which could be a speed difference. What I do now is just hunt with a fouled barrel once I am dialed in.

[cuda]

I do not clean my barrels at all it seems that a dirty barrel seals around the bullet better and gets better groups. A friend clean his barrel at it takes 5 or 6 shot before it settles back in again and start grouping again. I would wait awhile and see what a dirty barrel will shoot good. Then just shoot it dirty for awhile and see how it shoots. I use 69gr of IMR4198 with a Barnes 290gr TEZ and a lubed wad in my 45 Stevens McGowan I have not cleaned the barrel since I put it on. You could use more powder and make it shoot faster and flatter before you order your new dials. A 195 is a light bullet so it will not recoil much more if step up the charge a little.

[rangeball]

Dirtboy, any chance you were blowing sabots? My pacnor is on the tight side, and I blow sabots at 62gr, had to back off to 60gr in temps similar to what you shot to avoid it.

The sst is .400 already, only reason to knurl is if the fit in the hsb is too easy to load, something you don't hear about very often with a pacnor as they are usually .449-.450 on the lands. If you had above medium loading pressure, you may be stressing the sabot during loading making it more susceptible to failure.

[dirtboy]

When I got the high reading on the first shot it was a dirty barrel I would say around 15 shots but it had been in the safe all week. The second shot a little lower and the next 4 shots were very close to each other within 20-40fps. Rangeball I assume when you blow a sabot your accuracy goes down. I did not get the best group that day I think it was almost 2 inches and it was a perfect horizontal line. I did not try to find the sabots that day either. It should be cooler this weekend here so I hope to shoot some more. Bow season starts this weekend so i have alot to do. Thanks

[Richard]

If you got a two inch group, you did not blow a sabot.
That clean barrel shot is possible since the smooth pliable sabot will mate very closely with the smooth bore. IMO? Once the bore gets dirty the seal is not as good. So unless you plan on cleaning after every shot, just foul the barrel and go from there. I used to clean after every shot and it did work well, just a PITA! NO more. I will shoot my entire range session (20 to 40 shots) without cleaning. If you go from shooting sabots to sabot-less? Use one shot as a fouler/cleaner to remove any plastic build up before shooting for group.
Richard

[rangeball]

Yeah if it still grouped, most likely you weren't blowing sabots.