I have a Tikka T3X chambered in 6.5 Creedmoor. It has between 750 and 1000 rounds through it at this point.
I have mostly shot 142 gr. SMK over 42.6 grs. of H4350. Labradar says velocity averages 2740 fps.
I clean with M-Pro 7 regularly and keep the rifle i a climate controlled room when not in use.
I recently purchased 147 gr. ELD-Match bullets and using the Hornady OAL gauge, measured the distance to the lands.
Long lead up...
While doing that I decided to check and see if there were any changes. The SMKs measured 25/1000s longer than the original measurement. I checked several other projectiles that I have used like 140 gr. VLD-H and 140 gr. ELD-Match bullets and they all measured .025" more than the original measurement.
I can imagine that this could mean many things ranging from some wear on the initial length of the lands to significant erosion.
I know you are going to ask me how it shoots and I am not sure. Instead of not reacting to this discovery, I changed the seating depth to be .020 off the new measurement and the groups have opened up considerably. I have also had to switch to a new lot of H4350 and it does not seem to make as much velocity as the previous lot. Even less velocity than the extra seating depth would account for.
Thanks for your advice,
Edited to fix 750-1000 rounds.This message has been edited. Last edited by: henryrifle,
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about too much
I would think that the wear you see is genuine. As Nikon says, barrels are consumables.
Work up a new load with your newlot of powder.
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I had to read it a few times. I think you mean you had between 750 and 1,000 rounds through it; the 100 threw me off at first.
Yes, it is erosion and now you are trying to change many things at the same time. Let we say that if the precision had not degraded before you measured, why in the heck did you change the seating depth? Doing so modified the load as it decreased the internal pressure and may have thrown you out of a node.
Changing powder lots brings in its own set of problems, which is why I buy powder in 16 or 20 pound lots. But since it's a new lot, you need to retune the load.
The 6.5CM is not known as a barrel burner like the 6.5-284, BUT you burn almost as much powder in your case as I do in mine, and your bore is smaller, so it wears out faster. A .308 barrel will last me at least 4000 rounds and I don't chase the lands. I would expect a 6.5 CM to last at least 2000 to 2500 rounds for my precision requirements.
I think you have a lot of life left in it, but it would not hurt to borescope it to make sure it's just normal erosion.
.020 over 750-1000rds ain't nothing!
One of my Dasher barrels has moved about .100 still shoots lights out. My experience ALL my barrels move .010 within the first couple hundred rounds.
Most likely you simply need to get back to your previous velocity with the new lot of powder to get back in your node.
Don't borescope your barrel.
My first somewhat custom rifle was a 6.5CM, sold the 26" Kreiger/R700 barreled action with 2800rds, still shooting as well as I could shoot it. 44.5/4350/130vld/up against 3000fps.
Afraid of what you might see? :-)
NikonUser - There is no good answer to why I changed anything. I can't believe I did it. Would like to think I am smarter than that but clearly not.
offgrid - that is an interesting datapoint.
Next trip out I will be using the tried and true specifications with the only change being the new lot of powder. I can load at the range so I can be prepared to experiment a little.
Bonus question: I use StrelokPro for a ballistic calculator. Labradar says my favorite load has a muzzle velocity of 2740 fps. When shooting out to a known distance of 1000 yards and "truing" the velocity back in the program using the actual MOA (27.5) it took to hit the target, I get a MV of 2831. That is a big difference. There is a lot of setup in the calculator and I have double checked it all and found no mistakes. The app considers local density altitude obtained from the web and I am using multi-bc using G7 numbers.
Thanks for the feedback
It's always about how it shoots. Stop chasing numbers. If the original loads is shooting well, why change things? Yes you will get throat erosion shooting smaller bores with max loads.
IF YOU AREN'T HANDLOADING, YOU AREN'T SHOOTING ENOUGH!
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Maybe the BC values are overestimated.
I retired my 6.5 Creedmoor Barlein barrel at just over 3,200 rounds. Virtually all rounds down the tube were Hornady factory ammo -- a mix of 140 Amax and 140 ELD-M. I pulled the barrel early in this year's competition season, as I didn't have confidence in the old barrel's accuracy at an upcoming ELR match -- where a few targets would be at 1700 yards and many would be over 800 yards.
While shooting with my gunsmith at a subsequent match, my 'smith said he put a bore scope on the old barrel. In his words:
- I figured you had shot the shit out of the barrel.
- Your bullets had a large jump to the lands. (He didn't measure the jump, but stated it was substantial.)
Even with a large jump and substantial fire cracking in the throat, that barrel shot well. Only when I got out to 700+ yards did I see an occasional WTF low flyer. I generally throw a shot high when my technique falters, so low shots were a warning sign. I didn't test MV on the old barrel before pulling it, but its ballistics remained true to JBM drop numbers.
JBM hasn't matched up exactly to my 6.5 Creedmoor MV figures. IIRC, 140 AMax clocked in around 2800, but 2770 worked better in JBM. Switching to 140 ELD-M, MV of 2790 worked well with 2800 in JBM. With my new Bartlein barrel, 140 ELD-M MV clocks in at just under 2800, but 2820 in JBM is the best fit.
+1 to fredj338's comments
What's the barrel length of your old and new 6.5 CM barrels? Mine is 24".
26" for both the original and replacement Bartlein barrels
Hey fritz, thanks for the data point. So you're saying that at about 3000 rounds the 6.5CM barrel becomes suspect. I haven't a clue about the rate of fire you're used to in your environment. What will happen in my environment, is that in one day, we can shoot about 80-90 rounds, in three groups. The timeframe to shoot the 25-30 rounds is 30 minutes or so, but it's usually much faster than that; I have been know to get off my rounds in less than 12 minutes, but other times, I will use the full 30-some minutes. If I have a condition nailed, I can get rounds off as quickly as the target puller can service the target, and I've had some great pullers that can do that in under 8 seconds. This combination is rare, but it happens.
When I get off the line, my barrel is usually way to hot to touch it, even at 32 inches out. I know that does damage to the bore, but, barrels are consumables.
Would you be so kind as to describe your rate of fire? Are there times, when it's fast and furious or do you just get a half dozen shots off and move to another position or what?
Rate of fire varies a lot from match to match. Highest rates 8-10 rounds in 90-120 seconds for a stage in some matches. Well, assuming I can find and get on all the targets. Such matches are really tough for me.
Most match stages have more casual rates of fire, say 6-8 rounds in 2-3 minutes, maybe 10 rounds in 4 minutes. The trend in matches is to push us for more shots in less time. Which for me just seems to be less shots.....
My barrel is definitely hot in the longer & faster strings. It's just warm on the slower ones. Time between strings can be anywhere from 5 to 20 minutes -- depends on walking distance between stages and number of shooters in squads. On really hot days the barrel sometimes is still warm when I begin firing the next stage.
I've heard of competition shooters pulling 6.5 barrels as soon as 2,000 rounds, and as late as 4,000 rounds.
Thank you, very interesting. When you say 8-10 rounds in 3-4 minutes. Is that the total number of rounds for that stage? How many rounds total would you fire in a match or a day?
Yeah, I figured the 6.5CM would eat a barrel faster than a .308. It's still a lot better than the 6.5-284. The F-Openers used to drop their barrels at about 1000-1200 rounds. Now with the 7mm, they go closer to 3000 or more.
Yes, that's would be the maximum for a given stage. Max could be as little as 5 or 6, but generally no more than 10. Every now and then a 12-round stage occurs, which is one reason those of us with 10-round mags have a velcro 2-round holder just forward of the action.
In general, when we have to search for and range distance to targets, the round count is lower. When steel targets are easy to find (painted white, with target indicator numbers nearby) and distances are known, the round count increases and time decreases.
It can vary greatly. With 90-120 second stages on a "square range" match, round count could be 120+ if the shooter acquires targets well and moves quickly between shooting positions. Definitely more barrel wear on such days.
Hike-and-shoot matches are definitely lower. The Steel Safari match has a max of 48 rounds per day. I probably shot 30-40 rounds each day, meaning I couldn't find some targets and timed out on some stages. The guy behind me this year fired only 20-ish rounds on two of the three days, as he really struggled to find targets.
In a match two weeks ago I fired 110-120 rounds over the 2 days. Max round count was 200 for the match, so I pretty much sucked on target acquisition, movement between shooting positions, and time management.
Thanks for the great write-up; it does sound like a lot of fun.
I might be looking for a different challenge now and that might be something to look at. I have this AR-10...
Steel matches are a fun game...in their own warped way. You definitely have the trigger pulling and wind reading experience for it.
I don't recommend starting with a true PRS ("Precision Rifle Series") match. Depending on the venue, PRS can have lots of run and gun, and stupid short time constraints to acquire numerous targets from WTF positions on some stages. Such stages are often referred to "circus" stages. Locally, we call them "special olympics" stages. A better into would be a more casual match with mainly prone positions, reasonable time constraints, and relatively easy to see targets.
In my neck of the woods, the sporting rifle match on the north end of the NRA Whittington center is a good intro:
- 10 stages, with easy walks of 100-200 yards between stages
- 6 targets per stage, one shot per target -- hit or miss
- 4 minutes time limit, starting from standing position, rifle in hand or slung, all gear in hands or in pack
- 9 stages are shot from prone with bipod; 1 stage is shot from tripod or shooting sticks
- roughly 1.5 MOA to 3 MOA targets, at distances from 250 to 800 yards
- low key, friendly atmosphere, minimal entry fee, no prize table, minimal "gaming"
Unfortunately, I don't know much about the match options in your area.
With apologies to henryrifle for blantantly hijacking his thread.
Thanks for the info fritz, that's very interesting.
Yeah, I've developed some measure of skill at pulling a trigger and looking at flags, mirage, etc and it may be fun to try something else. I've started participating in some rimfire competitions at a local club, of which I am a member. I can see that the scope I have on my tricked out 10/22 needs to be upgraded and I have that lined up already.
I have a friend who is a gunsmith and his shop is not far from me. He also runs PRS-style matches every month and he has been pushing me to come out and shoot with them. Maybe I'll try that.
I've been competing in different disciplines long enough to know that if I go to a real PRS match, I would get my clock cleaned, taken apart, and handed to me in a nice little packaging. I also know that I would not feel bad about it one bit because I know everyone needs to start at the beginning. Maybe I could put my marksmanship to some use in other competitions.
I also know that my AR-10 is nowhere near as precise as my F-TR match rifle and the load I currently use in it is not using good bullets, just cheap run-of-the-mill 175gr SMK junk in a Winchester case. It would be interesting to see if I could load a 180gr JLK to mag-length.
No apologies needed on the thread drift. It has all kinds of good info in it.
I do have question that brings it back toward the original questions.
Do y'all use J-B Bore Cleaner or something similar to clean your barrels? If so, how often?
I ask because while I did create a lot of problems for myself, the one action that made the most difference was cleaning the barrel using J-B Cleaning Compound, VFG Pellets and Kroil.
My barrels have shown throat erosion of about .003 per 100 rounds. It is not constant, but this number is an overall average for my 6.5s. If accuracy is unchanged and you are using a bullet that jumps well, all you might see is a drop in muzzle velocity which you can adjusted in your ballistics app. If the speed is to too slow for your needs, you need to work up another load and adjust your seating depth.
As for your elevation drops from Strelok - I'll be honest, I've not seen stepped BCs for G7s. That said, the usual culprits for elevations being off are inputs. These include scope height, BCs, incorrect information for powder temp and MV change based on powder temp and distance to the target. Another is scope function. Many shooters do not test their scopes to verify the scope tracks and the elevation shifts are correct. You can modify your app to account for these variations but they need to be tested and a value calculated.
As to your last inquiry, the only cleaning I do is punch out the carbon and powder fouling after a range trip. When accuracy falls off, then I will take the copper out and go back to square one. This is why we all have mentioned accuracy...the bullet and target never lie. When you start getting fliers or groups start opening up, it's time to look at possible copper fouling.
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