Prairie Dog Match 3

[TheBelly]

Seems like there's a lot of difference between the MV of cold vs hot ammo and cold vs hot gun. I don't think it'll play too much at 100m, but at 600m it probably has a bigger effect. To what extent I can't say.

2706 fps vs 2595 fps is a lot of difference. If anything, it proves to me that I need to keep the ammo and the gun at consistent temps (as much as possible) during a shoot.

Myk, keeping up with your threads is teaching me a lot about shooting. Hopefully I'll get my poop in a group and be helpful to the rest here. Thanks for posting this up there.

[C Ward]

What powder ?

[islandermyk]

Varget 43.0 gr 175gr SMK HPBT

[islandermyk]

Seems like there's a lot of difference between the MV of cold vs hot ammo and cold vs hot gun. I don't think it'll play too much at 100m, but at 600m it probably has a bigger effect. To what extent I can't say.

2706 fps vs 2595 fps is a lot of difference. If anything, it proves to me that I need to keep the ammo and the gun at consistent temps (as much as possible) during a shoot.

Myk, keeping up with your threads is teaching me a lot about shooting. Hopefully I'll get my poop in a group and be helpful to the rest here. Thanks for posting this up there.

Just keep in mind... you need to try and experiment some of these things yourself to really see it yourself. I'm no expert.. just sharing my findings

[C Ward]

Varget in my 308 is about as temp insensitive as it gets . What type chrono? My Varget load was within 20 fps from 15 or so to 100 degrees . Did you confirm the velocity numbers at distance or just chrono data ?

43 grs should be in the 2650ish range usually , my load is 44 - 44.5 in a Win case and a BR2 with a 175 and this was 2730 out of a 26" Krieger .

[islandermyk]

Varget in my 308 is about as temp insensitive as it gets . What type chrono? My Varget load was within 20 fps from 15 or so to 100 degrees . Did you confirm the velocity numbers at distance or just chrono data ?

43 grs should be in the 2650ish range usually , my load is 44 - 44.5 in a Win case and a BR2 and this was 2730 out of a 26" Krieger .

I was using a Chrony F1... I was just using chrono data. Wrote down what it was reading out to me one shot after another.

I'm also using CCI's 250 Large Magnum Primers...
Mixed brass
shooting out of a 22 inch 11.25 twist heavy contour Bartlein barrel

I'm also starting to think that heavier barrels may keep in the heat longer.. much longer than thinner barrels..., but I can't confirm that.
I wonder how much of a difference in accuracy would be between the two... but this should be on another thread.

[Tim K]

I've had similar issues with powders that were supposed to be temperature insensitive. I think I traced the problem back to allowing a loaded round to sit in a hot chamber. On a string at a PD match, the first half or so would shoot normally, then I'd start getting a sticky bolt. I quit clambering a round as my first step to getting ready and now save it till last. I don't chamber now until the shooter in front of me gets their beep.

[C Ward]

There are a lot of variables there to look at .

The Chrony's are notorious for being off and all chrono's are sensitive to the light coditions . You want to set up and chrono in as close to the same conditions as possible with the light as close to straight above it . This way you can get some what repeatable numbers from them . You always want to take chrono numbers with a grain of salt untill the data is confirmed on targets at distance . The best way is to shoot groups on paper or big steel out past 700 and see where the actual impact is and back calculate the MV .

Using mixed brass iss a bad idea , I don't sort by weight like the bench rest guy's but it is all the same brand and preferably the same lot . The case capacity variations brand to brand will lead to big ES and SD issue's .

I try to stay away from magnum primers unless I have to because in smaller calibers they can lead to pressure wierdness for lack of a better term .

My Bartlien's in 308 and 6.5 have both been " fast " barrels . I would suspect at 22 inches 2675 - 2700 ish should be easily attainable . A thinner barrel is going to heat up way faster than a heavy one will , it may disipate the heat faster but it will take way less time to get hot .

Not letting the round cook in the chamber is always a good idea .

There is a really good book about the reloading process the Glenn Zediker wrote that has ton's of info in it , Reloading For Competition IIRC . If you google his name it will come up .

Vertical from velocity unless it is a stupid huge jump typically isn't going to show till past 500 yards .

[ColoWyo]

I agree with C Ward. Mixed brass is bad juju. I would try to at least stick with the same brand. I never had velocity swings with Varget. H4350 seems pretty damn good as well.

I've got a metric shit ton of used Winchester brass in 308 if you need some 100 or so.

[islandermyk]

There are a lot of variables there to look at .

The Chrony's are notorious for being off and all chrono's are sensitive to the light coditions . You want to set up and chrono in as close to the same conditions as possible with the light as close to straight above it . This way you can get some what repeatable numbers from them . You always want to take chrono numbers with a grain of salt untill the data is confirmed on targets at distance . The best way is to shoot groups on paper or big steel out past 700 and see where the actual impact is and back calculate the MV .

Using mixed brass iss a bad idea , I don't sort by weight like the bench rest guy's but it is all the same brand and preferably the same lot . The case capacity variations brand to brand will lead to big ES and SD issue's .

I try to stay away from magnum primers unless I have to because in smaller calibers they can lead to pressure wierdness for lack of a better term .

My Bartlien's in 308 and 6.5 have both been " fast " barrels . I would suspect at 22 inches 2675 - 2700 ish should be easily attainable . A thinner barrel is going to heat up way faster than a heavy one will , it may disipate the heat faster but it will take way less time to get hot .

Not letting the round cook in the chamber is always a good idea .

There is a really good book about the reloading process the Glenn Zediker wrote that has ton's of info in it , Reloading For Competition IIRC . If you google his name it will come up .

Vertical from velocity unless it is a stupid huge jump typically isn't going to show till past 500 yards .

I figured or had a questionable feeling about these chrono's. I had to shoot my 22lr passed it a few times to see if it'll give me some sort'a crazy reading. I was getting between 1200 and 900 fps out of my Savage Mark2 with some Federal rounds.

I'm pretty sure your right about getting some bad readings one way or the other. Believe me... I know when I'm not doing it correctly
This was taken a few months back*

This was all sorts of wrong! Not on a flat surface, not completely folded out, and God know what else I was doing completely wrong out there with this thing.... I was like sh*t.. I'm shooting really hot rounds
I will certainly keep your suggestions in mind. Thank you