New barrel, old loads?

[Allen Corneau]

I'm about to get my 6BR silhouette rifle re-barreled since getting it built and started in high power two years ago. I've managed to put about 3,500 rounds down the tube and the groups are opening up (from about 1/4 or 3/8 MOA out to 3/4 to 1"), so I'm guessing it's time.

Here's my question... out of the three different loads I shoot, I have five rounds of load "A" left over, 15 rounds of load "B", and 80 rounds of load "C". All three loads are different bullets and different powder.

I fully plan on going about testing/updating new loads in the new barrel, but what would you do with the old loads, especially the 80 rounds?

Obviously they are still good for fowlers/sighters and there's a chance that the current loads will be good enough for practice, but what if they aren't? Would you pull all the bullets, dump the powder back in the jug, and just reload them with the new loads?

I try to make sure all my brass stays on track with having the same number of firings and I'd rather not have these 100 or so thrice-fired rounds lingering on the shelf while the others get their 4th, 5th, or 6th firing if I can help it.

Thanks for any wisdom you might share.

 

[Mike Kohout]

IMO, ha! I would use the "C" lot to break-in the barrel, by your choice or the makers recommendations. After break-in then shoot 5 of "A" & "B" to see what the barrel likes and then the "C" lot. If nothing looks good then start from scratch, but you have not wasted any extra new supplies to find out.
Mikey

 

[HTSmith]

Depends on how "hot" they were and if the new barrel was chambered with the same reamer. Very likely the bullets will need to be seated deeper due to throat erosion on the old barrel. I've seen enough difference in reamers that they may or may not fit. Take the firing pin assembly out and check for fit.

 

[K22]

Assuming the case were sized to your old chamber via bump gauge and caliper, there is chance the old rounds would not chamber or cause excessive lug stress if too tight or excessively expand the case if too loose. You should be able to safety verify proper chamber by removing the firing pin assembly. Other than that, I don't think there is good answer to your question.

I had something similar when I re-barreled a few rifles. I do not "break in" barrels so that ruled out use of the loaded rounds for the dubious process. While I didn't have as many loaded rounds as you, I pulled the bullets, save them along with the powder and started anew with virgin cases.

If your loaded rounds chamber in the new barrel, then I suppose you can use them for practice and your "break in" process or in the best-case scenario, they meet your accuracy standards. For me, I just wanted to start with virgin cases since I paid a lot of money for the new barrels and wanted to eliminate as many variables as possible.

 

[Walt Krafft]

Shoot them. Depending on your requirements they may work fine. For XTC my T2K has had lots of barrels screwed on. I have not had to change loads once in 20 years. Am I shooting benchrest? No, standing at 200 yards 1/2 or 1/4 moa is hard to determine.

 

[Wottchitt]

It worries me that you might have a tighter new barrel than the old one. That would send pressures up, IMO.

 

[Kracken McGraw]

Steel, going to the dump to shoot cans or rats. I hope there is still fun things to do out there.

 

[Herzo]

I would suggest that you cut your load back 5 to 10% prior to committing to your existing loads. You should also verify that your headspace is within a safe margin of your old loads.

 

[Will Henry]

It really depends on how hot you loaded them. Since most people shooting a BR for M-S load them to the nuts, they might be fairly warm. As far as load development is concerned, I think you would have to go out of your way to find a load in a 6BR which would not shoot well enough for silhouette. The only issue is taking the rams down. Bottom line, if they are not too hot, shoot them for practice. I can only speak for myself, but when I miss, it isn't because the rifle isn't accurate enough; it's because i pulled the trigger when the crosshairs weren't on the animal. WH

 

[Allen Corneau]

Thanks for the replies so far. A few clarifications...

1. The new barrel will be put on by the same 'smith that did the first one, so should be done the same. (Will confirm when I drop it off with him.)
2. The barrel is the same twist rate and will end up the same length at 26".
3. Load A (5X) is a very soft load for Chickens (23gr. N135, 87gr. VLD)
4. Load B (15X) is a hot-ish load for Rams (30gr. N150, 115gr. VLD)
5. Load C (80X) is a middle of the road load for Pigs and Turkeys (28gr. N140, 95gr. VLD).

I'm really curious to find out how different the final loads for the new barrel will be.

 

[joshb]

It worries me that you might have a tighter new barrel than the old one. That would send pressures up, IMO.

Yup…I’d start over and save the old rounds until you verify the new load for that new barrel.

 

[Allen Corneau]

Wanted to circle back around to this thread to let folks know what I ended up doing.

Since I'm shooting various Berger VLD bullets (87's, 95's, and 115's) I was curious about the recommendation of starting load development with seating depth first. (Berger's article on VLD seating depth here.)

I took about 60 of the 80 rounds of the leftover 95 VLD's; carefully pulled the bullets using a collet-style bullet-puller; resized the neck with a bushing neck sizer (the cases had already been full-length sized); then reseated the bullets about 0.010" from the lands.

I then took all my stuff, including an arbor press and Wilson in-line seating die to the range. Since I had swapped on a different scope on the rifle, I used the last five old 87 VLD loads to sight-in the scope, then three shots of the old 95's to refine the zero on paper.

I then did a set of seating depth tests based on the methodology stated in the Berger article but with a few small changes. I did five-shot groups instead of their recommended 2 X 3-shot groups, and I moved 0.030" per group rather than the 0.040" they mention (except where I goofed and jumped 35).

Measurements using my Forster datum tool and the five-shot group size (C-t-C):

• 1.805" was 0.93"
• 1.775" was 0.46"
• 1.745" was 1.25"
• 1.710" was 0.67"
• 1.670" was 0.32"

Did some more three-shot groups +/- 0.005" on either side of 1.670" and it seemed to be pretty stable in that range. I need to try some two-thou increments, but I ran out of time and had to get going. For reference, my old barrel liked the 95's at 1.715".

All in all, I was really happy that I was able to hit that kind of grouping with just messing with seating depth while using the old barrel's preferred powder charge. Next batch of testing for this load will be +/- one and two-tenths of powder to see what changes and then final seating depth.

After that, then I get to move on to the Berger 115's!

 

[spaniel]

I'd shoot them for practice in the old barrel so you can resize the brass to dimensions known to fit the new chamber.

I had a 243AI barrel which was getting end of life, and I have 200 rounds loaded for it. Accuracy was not what I wanted for prairie dogs anymore, so I elected to spin on the new barrel I had for it. I checked base to shoulder dimensions and everything matched up, and test fired a few rounds to sight it in. Everything was fine. When we got on the hunt I finished off that box, then realized the other 3 boxes were all just a sliver away from chambering. The rifle was down for the trip. Best I can figure the body taper was a hare off somewhere, as the comparator couldn't pick up the difference. FL sized with .002" bump, could feel something push on the body before the shoulder hit. Then everything worked.