Load development during barrel break in

[Nvhunter92]

I just picked up a Christenson arms Mesa Long Range in 7mm. Per the manual it says to clean after each shot for the first 10 the clean after every 5 for the next 50. I need to fire form 50 rounds of nosler brass anyways so that works out. My plan right now is to shoot the first 10 shots at a mid range powder charge then for the next 50 I will do a ladder test starting at the medium charge I used for the first 10 shots and working up to max since I will be able to shoot 5 shot groups between cleanings. Is this a waste of time since the barrel might not still be broken in? Christenson claims their barrels are hand lapped already. Would I be better just using the medium powder charge throughout the whole process and maybe working on seating depths after the first 10 shots? I've read that barrel life on a 7mm rem mag is around 1000 and I'd hate to use up around 200 shots just to break it in and develop a load. Any suggestions would be appreciated.

 

[RockyMtnMT]

I stop breaking in when copper stops showing. Then I shoot and clean as normal. Keep in mind some bullets foul much more than others. Last few factory rifles I did did not show any fouling to speak of after a few shots with our bullets.

Steve

 

[HARPERC]

I think it's over doing it, but from a warranty standpoint it may be useful.

I haven't had as many new barrels as some, but even in quality barrels there can be variations in how much break in is needed, and that seems to have changed over time.

I think it starts by asking:
1) What the goal of "break in" is.
2) I think the variables in cartridge, caliber, and bullet have a bigger role in the process than what we see in good quality barrels.
3) How we plan on using the rifle.
4) What cleaning theory we subscribe to, and how we plan to clean the rifle in the future. There are folks literally not cleaning until accuracy suffers, hundreds, even thousands of rounds, believing cleaning is more hazardous to bore life.
5) Your cleaning process.
6) Bullet/barrel coatings.

I was weaned on surplus corrosive military ammunition, and it took me a long time to let go of those habits.

 

[idahoorion]

Nvhunter92, lots of variables in the first 50. the brass has not formed, the barrel is speeding up, and the cleaning procedure is going to have you shooting a high percentage of shots that are foulers which you may or may not be able to tell anything anyway. after the 1st 50 is when I would get serious. once you find a load if you can get the speed of it then measure it later on (after the first couple hundred and see if it's changed and you can drop the charge back to keep in the sweet spot. IMO

have fun
Idahoorion

 

[Nvhunter92]

Nvhunter92, lots of variables in the first 50. the brass has not formed, the barrel is speeding up, and the cleaning procedure is going to have you shooting a high percentage of shots that are foulers which you may or may not be able to tell anything anyway. after the 1st 50 is when I would get serious. once you find a load if you can get the speed of it then measure it later on (after the first couple hundred and see if it's changed and you can drop the charge back to keep in the sweet spot. IMO

have fun
Idahoorion

That was what I was thinking, do you think finding a decent seating depth would be worth it during break in or will that most likely change once the brake in is complete? Would it be worth shooting a minimum load during break in just to minimize barrel wear due to a hotter load?

 

[ShtrRdy]

I would separate the break in process and load development process. When doing break in go by what the cleaning patches are telling you. What we're trying to do with break in is to burnish the frebore and leade area of the chamber. This is because when the chamber was cut the reamer was cutting metal away perpendicular to the bore. I've never had to fire 50 rounds to break in a barrel. It's usually been more like 25 rounds.

Then when you start load development you'll have some fire formed brass which improves accuracy.

 

[djfriesen]

If it was me, and I was going to fire all 50 rounds to break the barrel in, I would definitely play with seating depth on the 5 shot groups. It might not do for fine tuning, but I would use the data to get an idea (think the Berger seating method). I can't think of a reason not to.

 

[idahoorion]

That was what I was thinking, do you think finding a decent seating depth would be worth it during break in or will that most likely change once the brake in is complete? Would it be worth shooting a minimum load during break in just to minimize barrel wear due to a hotter load?

sure you can play with seating depths especially if you know the bullet you are going to try and shoot. in the long run let the barrel choose it's favorite bullet. H1000 and the 7RM go together like PB&J. and it has the added benefit of being a cooler burning powder. so if your chosen bullet weight has a good load listed for H1K give it a whirl.

Idahoorion

 

[Nvhunter92]

If it was me, and I was going to fire all 50 rounds to break the barrel in, I would definitely play with seating depth on the 5 shot groups. It might not do for fine tuning, but I would use the data to get an idea (think the Berger seating method). I can't think of a reason not to.

Do you think that if I found a seating depth that my rifle liked with a moderate powder charge that my rifle may or may not like, that seating depth would still be a preferred seating depth at a different (more accurate) charge weight when I start testing charge weights?

 

[J E Custom]

I would do as the barrel maker says but once the barrel shows little signs of fouling you could start load development with reduced loads to find out what powder, bullet and primer combination it likes.

I would still clean after each 5 shot test group also allow the barrel some time to stay cool. This would not void your warranty but could give you a head start on load development. During this process I would use a chronograph to look at SDs only to verify the powder, bullet primer combinations compatibility with your rifle and by the time you get to 50 shots the barrel will be broke in and the load will be well on its way.

If you have good SDs, I would start experimenting with bullet seating depth for the best accuracy.

J E CUSTOM

 

[brentc]

I don't believe in a specific process outside of putting rounds through your barrel and cleaning after each 20 rounds until your velocity stabilizes after ~ 75 rounds. This is when you're barrel is truly broken in. You'll know when you hit this point because you'll notice a velocity increase of about 70-80 fps with known loads. Final load development should occur after your velocity stabilizes.

 

[J E Custom]

After talking to many well known barrel makers that recommended a brake in Procedure and asking the purpose of a shoot and clean procedure each one said that this method "Seasoned" the barrel and did not allow any fouling to protect the bore during this time. When a shot is fired in a new barrel, there is some bullet fouling and even this one shot fouling will protect any discontinuities that may exist unless it is removed.

I also ask if there were any problems just shooting multiple rounds and then cleaning. The answer was unanimous no, but it would slow the brake in process and that it would take longer to reach the full potential of their barrel. (Quote).

Most said that even though there barrels were hand lapped, that a proper/recommended brake in should not take over 15 to 20 shots. 10 shoot and clean, 5, 3 shot shoot and cleans, and the barrel is ready to shoot 5 shot groups as long as they are not in rapid succession. One of my favorite barrel makers even stated that these numbers are not cast in stone, and even though he uses the same procedure for all of his barrels that any where from 7 to 12 shoot and cleans may be necessary before the patches come clean and other premium barrels also have a range of shots that it takes before they stop fouling a reasonable amount.

So from all of these conversations, the truth is you can do break-in or not. The choice does not hurt the barrel ether way, it only effects the amount of shooting before the barrel is at its best,

In my opinion, A proper/recommended brake in has an accuracy advantage because less rounds are fired before the barrel is ready and the chance of uneven brake in is less because of fouling protecting bad/rough places in the bore. I have seen some of the best groups during the break in with cleaning between every round. So now I try to hold on the same POI and see if groups are good(This is also an indication that it likes the powder and bullet combination and I can start with this load and work up.

Factory barrels will take many more break in shots and may never reach a minimum fouling state. With these barrels sometimes it is best just to shoot them and let the copper fouling cover all of the rough places to get the best accuracy possible.

J E CUSTOM

 

[brentc]

I've done it both ways. A standard clean after every shot process and a no break-in method. The break in process made the rifle easier to clean earlier in its life, but the process did not help to speed up the velocity stabilization that occurs ~ 75 shots.

 

[J E Custom]

I've done it both ways. A standard clean after every shot process and a no break-in method. The break in process made the rifle easier to clean earlier in its life, but the process did not help to speed up the velocity stabilization that occurs ~ 75 shots.

I have not seen any significant change in velocity or the stability ether way but a major improvement in cleaning when a brake in is used. the only time I see a difference in velocity, is with different barrel brands. Some are faster than others in the beginning because of bore dimensions and finish.

The only time I check velocity after brake in and load development is if I make any change in any components (New powder lot) or cartridge case change (Batch or brand).

Normally I am done with brake in and load development long be for 75 rounds so this could have slipped through the radar, unless the SDs or POI changed.

Worth watching for.

J E CUSTOM