Low to high ES why or ?

[wywindsor]

The gun a 7mm prc Savage timberline. Cheap as it gets. I shot a powder test with many powders bt the 2 that stood out most were 565 and 4831sc. Both had a 5/8'' vertical over 4 tenths of powder at 500yards. I used 175 eldx bullets speed was 2808 to 2922 for both as well.

This weekend I loaded in the middle of both charges and shot the 565 at .020 to .005 in. With .005 increments at 900. Of course the wind gave me it's report instead of what I wanted. Wyoming. Indian for land of the wind. What Ii did find this weekend was the first of 3 was 2892 to 4 and the next back to 2912's + or -. I shot 4 foulers at 900. Drove the down to verify. Rinse and repeat over the next 21 shots. Why is the first always low FPS. All grouped pretty well for the conditions. Why

Thanks Ray

 

[ELR LVR]

The gun a 7mm prc Savage timberline. Cheap as it gets. I shot a powder test with many powders bt the 2 that stood out most were 565 and 4831sc. Both had a 5/8'' vertical over 4 tenths of powder at 500yards. I used 175 eldx bullets speed was 2808 to 2922 for both as well.

This weekend I loaded in the middle of both charges and shot the 565 at .020 to .005 in. With .005 increments at 900. Of course the wind gave me it's report instead of what I wanted. Wyoming. Indian for land of the wind. What Ii did find this weekend was the first of 3 was 2892 to 4 and the next back to 2912's + or -. I shot 4 foulers at 900. Drove the down to verify. Rinse and repeat over the next 21 shots. Why is the first always low FPS. All grouped pretty well for the conditions. Why

Thanks Ray

first few shots low velocity:
- cleaner barrel, fouling builds up ever so slightly per shot until an equilibrium is reached
- The gun/chamber starts getting warmer per each consecutive shot
---
Both reasons are why we fire a few "Fouler" shots before shooting a group, making an accurate assessment etc

 

[wywindsor]

Thanks. I just didn't see this when I shot the powder assessment. All were with in 12 t0 15 es. I shot these one shot at a time and drove down to verify each shot. Thanks.

 

[Doom]

I assume you are looking at this as a hunting rifle. In that case you want the barrel condition to be the same for the first shots (2-3) every time. This means you need to work with a clean barrel each time for those shots or a fouled barrel. My gut reaction is being a Savage it may take a few more shots to foul this barrel. It is also not outside the realm of possibility that it's just a statistical anomaly (sampling) for this test.

 

[Turkeytider]

The gun a 7mm prc Savage timberline. Cheap as it gets. I shot a powder test with many powders bt the 2 that stood out most were 565 and 4831sc. Both had a 5/8'' vertical over 4 tenths of powder at 500yards. I used 175 eldx bullets speed was 2808 to 2922 for both as well.

This weekend I loaded in the middle of both charges and shot the 565 at .020 to .005 in. With .005 increments at 900. Of course the wind gave me it's report instead of what I wanted. Wyoming. Indian for land of the wind. What Ii did find this weekend was the first of 3 was 2892 to 4 and the next back to 2912's + or -. I shot 4 foulers at 900. Drove the down to verify. Rinse and repeat over the next 21 shots. Why is the first always low FPS. All grouped pretty well for the conditions. Why

Thanks Ray

I’ve yet to see anything that convinces me that advanced hand loading isn’t a combination of science and art…..with a dollop of witchcraft thrown in for good measure!

 

[Straightshooter1]

I’ve yet to see anything that convinces me that advanced hand loading isn’t a combination of science and art…..with a dollop of witchcraft thrown in for good measure!

Rather than science and "art", I see it as science and craft. Take any craft and you find wide variations in how skilled people are at a craft.

 

[wywindsor]

Let me try to explain better. I shot 4 foulers to get on target. I then shot groups of three. I drove to the target between each group. Say a 5 to 7 minute apart. The first shot of every 3 shot group was the lower speed. I did not clean the gun until I got home.

My next test will be 4831sc same test as the 565.

 

[JFrank]

Let me try to explain better. I shot 4 foulers to get on target. I then shot groups of three. I drove to the target between each group. Say a 5 to 7 minute apart. The first shot of every 3 shot group was the lower speed. I did not clean the gun until I got home.

My next test will be 4831sc same test as the 565.

I wonder if there is something in the ignition hanging up.

 

[Coyotefurharvester]

A soft ignition on the first rd would point to pin/spring issue. Maybe something simple like lubication or spring contact with bolt body. With your data simple maintenance/lube check should show up on next chrono session.

 

[tdogg]

The first shot in every string is the coolest barrel (5-7 mins). Next two have a warm barrel, did you wait 5-7 mins between each shot?

How long is the next cartridge in the chamber before you fire it? I generally try to leave the bolt open for cooling between shots and to minimize the heating of the next cartridge before firing. I then chamber and fire quickly.

Cheers,
Toby

 

[wywindsor]

The first shot in every string is the coolest barrel (5-7 mins). Next two have a warm barrel, did you wait 5-7 mins between each shot?

How long is the next cartridge in the chamber before you fire it? I generally try to leave the bolt open for cooling between shots and to minimize the heating of the next cartridge before firing. I then chamber and fire quickly.

Cheers,
Toby

The first shot in every string is the coolest barrel (5-7 mins). Next two have a warm barrel, did you wait 5-7 mins between each shot?

How long is the next cartridge in the chamber before you fire it? I generally try to leave the bolt open for cooling between shots and to minimize the heating of the next cartridge before firing. I then chamber and fire quickly.

Cheers,
Toby

No on the 5 to 7 between shots. Less than 15 seconds from shot to shot.

 

[wywindsor]

Say the firing pin is hanging up. Why would shots 2 and 3 be any different? Time between shots being closer together? I'm going to clean the gun like normal oil the bolt and wait til the next range trip with the 4831sc test. Would have went to the range yesterday or today. but the roads were closed around here do to wind for high profile vehicles under 40k.

 

[Coyotefurharvester]

A friend bought a New High Country (Savage) for elk season. We ended up hunting in subzero temps. First shot opportunity, ftf, light primer strike. Cycle the bolt, aim shoot, dead elk. Stuff can happen on the first pin drop. I asked him if he had stripped the bolt and lubed it like I suggested. No it worked fine in early fall sight in. I don't trust factory bolt lube. First thing I would have done before mounting a scope.

 

[JFrank]

Say the firing pin is hanging up. Why would shots 2 and 3 be any different?

Hard to say, look for burrs or evidence of rubbing on the springs and pin.

Time between shots being closer together? I'm going to clean the gun like normal oil the bolt

I keep the internals of a bolt clean and dry.

 

[Doom]

Let me try to explain better. I shot 4 foulers to get on target. I then shot groups of three. I drove to the target between each group. Say a 5 to 7 minute apart. The first shot of every 3 shot group was the lower speed. I did not clean the gun until I got home.

My next test will be 4831sc same test as the 565.

Please post your velocity data, by group.