Just gave my highest count 6BR a JB cleaning, down to bare metal as seen with the Hawkeye. For those who have no personal experience with how many rounds before the beginning of firecracking in the throat area: a documented 1638, and compared to several other 6BR chamberings, with less rounds fired, I can find no trace of firecracking what-so-ever. The throat area on the "old" barrel looks identical to a new Krieger at 244 rounds. Barrel in question is a Hart, 1-8 twist, .272" no-turn neck, 26" length. First 1050 rounds fired were with the 95 gr. Berger VLD seated to touch with 31 grs. of Varget. The remaining 588 rounds have been with the 107 gr. Sierra # 1570 seated to touch with 30 grs. of Varget. All firing single shot at a slow pace with a basic cleaning every 20 to 30 rounds. As an added note, the original Lapua brass now has 31, 32, and 33 (depending on the box of 20 each), loadings, and continues to be problem free: primer pockets remain tight, no indication of splits or failures of any type, never annealed. ;D
6BR barrel life/ brass life
- Thread starter fdshuster
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Don't worry too much about slight fire-cracking visible to a bore-scope. My Savage with PacNor barrel shows a bit of that...
Earlier this week, piloted by my friend Joe, it put 3 rounds into .335" extreme edge to edge at TWO hundred yards. As best as we could measure (after subtracting one typical bullet hole size), the three shots composed .113" group or about 0.05 MOA. Again this was at 200 not 100! The same gun a few days before shot a .456" 5-shot group at 328 yards (300 meters), off the ground.
Load was 31.3 Varget with a Berger 95 .010" in lands, CCI 450
Earlier this week, piloted by my friend Joe, it put 3 rounds into .335" extreme edge to edge at TWO hundred yards. As best as we could measure (after subtracting one typical bullet hole size), the three shots composed .113" group or about 0.05 MOA. Again this was at 200 not 100! The same gun a few days before shot a .456" 5-shot group at 328 yards (300 meters), off the ground.
Load was 31.3 Varget with a Berger 95 .010" in lands, CCI 450
686: I check case lengths each time they are run into the Redding Type S neck bushing die, whether the shoulders are set back or not, and for the first 10 to 15 loadings, nothing changes. After that a few may grow from 1.558"/1.560" to 1.563"/1.565" (my chamber lengths are 1.570" as measured with the Sinclair gauge), so I'll trim them back to 1.560" max. Just did 60 of the high count cases (32 & 33 loadings), and 15 got a very light trimming of .002"/.003". Trimming requirements are minimal. Headspace lengths on my 3 .272" no-turn chambers (were all cut with my reamer, back to back) are 1.157", brass is interchangable, I like to keep a little pressure on bolt closing, and will push the shoulders back to 1.156" about every third or fourth loading, when I can feel just a little more pressure required than normal. Using a .267" bushing for the loaded round neck diameter of .2685"/.269". Another added note: check & verify your actual neck bushing size: a stamped .267" does not mean it really sizes to .267". Several of my bushings actually size .0015" and .002" smaller than "advertised".
That's some good info there! Thanks for sharing! I'm in the process of getting all the components together for my first 6BR build and was wondering what I could expect with barrel and brass life. I will be using a krieger 8 twist on trued rem 700 action, lapua brass, and a PTG reamer. I went with a .272 neck. I should have my reamer and stock this week and I plan to get this thing chambered and bedded the second week of august (on vacation). I will be glued to lathe til then! There ain't piece of scrap that has not been shanked and threaded for a 700!
"86": If you're getting your own reamer I would suggest you get the shortest freebore possible for the bullet(s) you plan on using. If starting with a .104" or some other lengthy freebore you will be limited in a short time of what type of short lighter weight bullets you'll be able to use, keep 'em touching the lands, and remain in the case neck. I recently had my .104" PTG reamer reground from .104" to a zero freebore, and I'm liking that one a lot more than the original. Even with the zero freebore I'm able to seat the longer heavyweights to touch the lands, the case neck is filled with the .243" diameter and only a portion of the heel of the boatail intrudes into the powder space. With the long barrel life of the 6BR, the short freebore extends that life even more. 
I agree being a fan of the shorter freebore myself. My favorite reamer for the 6BR is a .060 freebore which allows me to seat the Berger 105 VLD's with the bearing surface boattail junction right at the neck shoulder junction in new Lapua brass which is .010-.015 into the lands. This combination has shot extremely well in three different 6BR barrels.
I had a .104 freebore reamer that I sold since I could see absolutely no advantage on the target over the .060 with it's slightly added case capacity. The small velocity increase wasn't worth the extra powder in my own testing.
30.5 grains of Varget in Lapua brass over a CCI 450 with the Berger 105 hunting VLD seated .010-.015 into the lands has shot lights out in every barrel I have chambered with the .060 PTG reamer.
Since switching to cut rifled Kreiger and Bartlein barrels I've found barrel life to have increased quite a bit over the button rifled Shilens I had been using. Cut rifleing is the hot setup for extended barrel life all things being equal in my opinion.
Danny
I had a .104 freebore reamer that I sold since I could see absolutely no advantage on the target over the .060 with it's slightly added case capacity. The small velocity increase wasn't worth the extra powder in my own testing.
30.5 grains of Varget in Lapua brass over a CCI 450 with the Berger 105 hunting VLD seated .010-.015 into the lands has shot lights out in every barrel I have chambered with the .060 PTG reamer.
Since switching to cut rifled Kreiger and Bartlein barrels I've found barrel life to have increased quite a bit over the button rifled Shilens I had been using. Cut rifleing is the hot setup for extended barrel life all things being equal in my opinion.
Danny
Danny: We are on the same page, not only for reamer selection, but barrels also. I've always favored Hart button rifled, although have a number of Shilen's and Krieger's, but recently bought 2 Krieger barrels, one for 6ppc and the other for 6BR, and as good as the Hart's have always been, the Krieger's have moved into first place. Can't see any difference with my borescope, but they seem to have that little extra edge in grouping and ease of cleaning. The 6ppc was also cut with my PTG reamer, another at zero freebore/ base of the favored 68 gr. Berger sits at the neck/.shoulder joint with the ogive touching/ top of powder column (28 grs. N133) touching the base of the seated bullet. To me, the best of all worlds.
I'm with ya on the kriegers. The last 8 rifles that my father built have been on kriegers and they all shoot great. There was one shilen in there somewhere and it shoots well to but I personally prefer kriegers. I had the same thought on freebore lenght as well. I got Dave Kiff on the phone when I was ordering my reamer and we had a lenghty discussion about freebore and with bullets I plan to use he recommended a 0.077", so thats whats coming. I hope I made a good choice. :-\ His theory was the same as what yall stated about having the option of getting those light bullets into the lands as the throat wears and still be able to keep the vlds from hittin the bottom of the case : I'll be the first to tell ya I'm new to the 6BR and finally am able to make one happen. Is been a long time goal to add one to the family.
I'll be the first to tell ya I'm new to the 6BR and finally am able to make one happen. Is been a long time goal to add one to the family."86": Not a bad idea to go with the .077" freebore, keep the reamer and for $25 at any time in the future you can have it reground to any shorter dimension. I did have a 223 Rem. reamer done with .074" freebore, and that one is working great, for both my son's rifle and mine. Seats all bullets to touch from the 55 gr. V-Max to the 80 gr. Sierra MatchKing, with plenty of bullet shank diameter in the case neck, and it too could be reground to anything shorter. 
Solid practice, not trimming until case grows. You'll likely not reach critical before brass wears out-but when they get long, trim to 1.156. Hard to go wrong with that.
dmoran
Donovan Moran
1st - this is an 8-year old thread
And believe it may be, trim to 1.556", not 1.156"
Again, just saying.....
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Yeah,,,,,,,,,,, old thread for sure, but it got me thinking. So I plotted the Mean Radius, also known as Average-to-Center, for the 2156 rounds down the barrel of my 6mm BR Norma on the Y axis. The X axis is the date.
I scan nearly every target other than my F-Class match targets and measure them using On Target software, so the data is pretty accurate. Be aware that this data includes nearly every round, not just my "good stuff". During load development, for example, I expect that the heaviest and lightest charge weights will be less than optimum. The same for most other testing parameters. For instance, I expect some bullets to perform not as well as the ones I eventually settle in on for making my best match ammo. So you could expect spikes in how well the ammo performs, some good and some not so good.
The red trend line on the graph is a second order polynomial and it shows that group size initially decreases which makes sense because that's when I'm zeroing in on the best recipe. It takes a while to fine tune all the variables and, one would hope, that over time it would be possible to develop a really good match ammo recipe.
Then, as time goes on, the accuracy starts to degrade a little bit as the barrel ages. That's expected too since no matter how gentle the 6mm BR round is on barrel life, there is bound to be some degradation. Anyhow, here's the chart, for what it's worth.
EDITED TO ADD: These are mostly 5 shot groups at 100 yards.
I scan nearly every target other than my F-Class match targets and measure them using On Target software, so the data is pretty accurate. Be aware that this data includes nearly every round, not just my "good stuff". During load development, for example, I expect that the heaviest and lightest charge weights will be less than optimum. The same for most other testing parameters. For instance, I expect some bullets to perform not as well as the ones I eventually settle in on for making my best match ammo. So you could expect spikes in how well the ammo performs, some good and some not so good.
The red trend line on the graph is a second order polynomial and it shows that group size initially decreases which makes sense because that's when I'm zeroing in on the best recipe. It takes a while to fine tune all the variables and, one would hope, that over time it would be possible to develop a really good match ammo recipe.
Then, as time goes on, the accuracy starts to degrade a little bit as the barrel ages. That's expected too since no matter how gentle the 6mm BR round is on barrel life, there is bound to be some degradation. Anyhow, here's the chart, for what it's worth.
EDITED TO ADD: These are mostly 5 shot groups at 100 yards.
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