6.5 grendal and 748

PaulS · Posted: Mon Feb 21, 2022 1:51 am Post subject: Re: 6.5 grendal and 748

Slimjim,
That is very similar to what I do. I like to make sure it gets tested over a wide range of weather conditions. I shoot a five shot group into a double target take the front one down and place a new target over the rear one - carefully aligned Clean the rifle and fire 5 more rounds. I change targets twice more so I have four 5 shot groups and a 20 round aggregate. I'll shoot that regimen over the course of a year - cool, wet, hot, and dry and compare the aggregate targets. After that I fire a couple of rounds before I clean it to take it hunting.

slimjim · Posted: Mon Feb 21, 2022 8:15 am Post subject: Re: 6.5 grendal and 748

PaulS wrote:

I'll shoot that regimen over the course of a year - cool, wet, hot, and dry and compare the aggregate targets. After that I fire a couple of rounds before I clean it to take it hunting.

Paul, didn't you mean to say you fire a couple of rounds AFTER you clean the rifle before you take it hunting? The point of impact of my rifles with a clean bore is different than a fouled bore which results in a significant miss distance at the ranges I have to hunt pronghorn and elk at.

PaulS · Posted: Wed Feb 23, 2022 1:26 am Post subject: Re: 6.5 grendal and 748

Nope. The impact with a clean bore is the same as with the next four shots and it stays there until it gets too dirty. It is a rifle that has had many rounds through it.

DallanC · Site Admin Joined: Jan 18, 2005 Posts: 3572 Location: Utah

Interesting, I did a very deep cleaning on my wife's hunting rifle. We took it out and did a 10 round break-in string with a load I was working up. I found while accuracy was ok for break-in, what startled me was the velocity change.

The first shot was the slowest, second was fractionally faster than the first. Each subsequent shot got faster and faster until it stabilized around shot #8. The final 3 were in the expected velocity range for the load.

It certainly is going to be a gun specific phenomenon, each barrel is different. Some may indeed work great being spotlessly clean, Most of the guns I have like it a bit dirty.

-DallanC

Vince · Posted: Wed Feb 23, 2022 7:29 pm Post subject: Re: 6.5 grendal and 748

DallanC wrote:

Interesting, I did a very deep cleaning on my wife's hunting rifle. We took it out and did a 10 round break-in string with a load I was working up. I found while accuracy was ok for break-in, what startled me was the velocity change.

The first shot was the slowest, second was fractionally faster than the first. Each subsequent shot got faster and faster until it stabilized around shot #8. The final 3 were in the expected velocity range for the load.

It certainly is going to be a gun specific phenomenon, each barrel is different. Some may indeed work great being spotlessly clean, Most of the guns I have like it a bit dirty.

-DallanC

You will probably find that a bit of fouling in the bore increased pressures a little...increased pressure would equate to increased velocities mate.

Dawgdad · Posted: Sat Feb 26, 2022 6:24 am Post subject: Re: 6.5 grendal and 748

Maybe Vince but I have seen that happen after a deep clean and it usually was because I had re -exposed any roughness in the bore and it took a few shots to lay down a little copper over those spots and make a uniform surface in the bore. Bore scopes are the Devil. They let you see things you cannot unsee.