Anyone ever have this happen before? I've been shooting 105 AMAX bullets from my factory Rem 700 .243 with 26" 1:9.125 twist barrel since I got it and they seemed fine, but after about 150 rounds through it, I had a few keyholes with the starting loads of retumbo which were fine before. Some slightly hotter loads seemed to straighten out. I will test them some more, but I wondered if I could be losing some spin velocity as the rifling wears in?? I try to keep it very clean so I don't think it is fouling. It's soaked in Butch's Bore Shine and brushed until patches come out clean each time I shoot. There is some slight green on the patch, but how to tell if it's from the jag or barrel? The only difference I can think of was I used Federal brass instead of Winchester this time. Any thoughts??
Re: Bullets were fine, now keyholing after 150 rounds?
How clean are you keeping "very clean"... most times rifle barrels are ruined by cleaning not by fouling. The point blank BR guys shoot out a barrel in 3-500 rounds some times, and they scrub the shit out of their barrels. The LR guys on here that consistently shoot sub MOA rifles long ranges generally say to clean it when the accuracy is tailing off, then it comes back.
I clean my 30-06 about every 500 rounds or so, it shoots better dirty.
How clean are you keeping "very clean"... most times rifle barrels are ruined by cleaning not by fouling. The point blank BR guys shoot out a barrel in 3-500 rounds some times, and they scrub the shit out of their barrels. The LR guys on here that consistently shoot sub MOA rifles long ranges generally say to clean it when the accuracy is tailing off, then it comes back.
I clean my 30-06 about every 500 rounds or so, it shoots better dirty.
Re: Bullets were fine, now keyholing after 150 rounds?
What's your velocity? The faster you push it, the better off you are. So, maximize your speed, and this might help. I am showing a 1:8 twist as minimum. So a 1:9.125 is a little slow for it.
Also, don't clean it that hard. Run a few patches with solvent on it, and consider it clean.
What's your velocity? The faster you push it, the better off you are. So, maximize your speed, and this might help. I am showing a 1:8 twist as minimum. So a 1:9.125 is a little slow for it.
Also, don't clean it that hard. Run a few patches with solvent on it, and consider it clean.
Re: Bullets were fine, now keyholing after 150 rounds?
Bohem: The rifle has been to the range 4 times with 30-40 rounds fired each time. After each trip I would, using a bore guide and coated one piece rod, run a few patches soaked in Butch's Bore Shine through the barrel and let it soak for 15-20 minutes. Patches continued to look dirty after this so I brushed it about 10-15 strokes each time, then ran more patches and they would start to come out fairly clean. A little bit of green but I thought that was my bronze jag? Is this too much cleaning do you think? This is all more or less according to Butch's own article he wrote on gun cleaning from the reloading manual I have. If I had a 'benchmark' to compare to I could see if accuracy drops off and just clean then but each time I have been testing 4-6 round groups of different loadings/seating depths etc. Hopefully I have not damaged my new (and first!) rifle already, surely it must be tougher than that!??
Bohem: The rifle has been to the range 4 times with 30-40 rounds fired each time. After each trip I would, using a bore guide and coated one piece rod, run a few patches soaked in Butch's Bore Shine through the barrel and let it soak for 15-20 minutes. Patches continued to look dirty after this so I brushed it about 10-15 strokes each time, then ran more patches and they would start to come out fairly clean. A little bit of green but I thought that was my bronze jag? Is this too much cleaning do you think? This is all more or less according to Butch's own article he wrote on gun cleaning from the reloading manual I have. If I had a 'benchmark' to compare to I could see if accuracy drops off and just clean then but each time I have been testing 4-6 round groups of different loadings/seating depths etc. Hopefully I have not damaged my new (and first!) rifle already, surely it must be tougher than that!??
Re: Bullets were fine, now keyholing after 150 rounds?
I don't buy that you need even close to a 1 in 8" twist, I shot them out of my 1 in 10" 6mm Ackley and they were fine to to 600 yards.
I don't buy that you need even close to a 1 in 8" twist, I shot them out of my 1 in 10" 6mm Ackley and they were fine to to 600 yards.
Re: Bullets were fine, now keyholing after 150 rounds?
Chad: Sorry, no chrony yet (on the wish list!). The hotter loads did seem to straighten them out, so I'll definitely experiment with that. I'm really curious about why now though and not the other trips with the same starting loads. Thanks for the cleaning advice, I guess I will have to experiment and see what works best with this gun with the least brushing would be the best compromise here?
Chad: Sorry, no chrony yet (on the wish list!). The hotter loads did seem to straighten them out, so I'll definitely experiment with that. I'm really curious about why now though and not the other trips with the same starting loads. Thanks for the cleaning advice, I guess I will have to experiment and see what works best with this gun with the least brushing would be the best compromise here?
Re: Bullets were fine, now keyholing after 150 rounds?
What temps/altitude were you shooting the first 150 rounds? If they were very borderline then I'd think that the environmetal factors could have changed just enough.
What temps/altitude were you shooting the first 150 rounds? If they were very borderline then I'd think that the environmetal factors could have changed just enough.
Re: Bullets were fine, now keyholing after 150 rounds?
Jasonk: They were shot at the same altitude (same pit), and close in temperature as well, say +/- 5 degrees celcius (+/- 10 F). Would it be possible for a powder to be that sensitive to conditions? Retumbo is a so-called 'extreme' powder also - meant to be relatively consistent with temp?
Jasonk: They were shot at the same altitude (same pit), and close in temperature as well, say +/- 5 degrees celcius (+/- 10 F). Would it be possible for a powder to be that sensitive to conditions? Retumbo is a so-called 'extreme' powder also - meant to be relatively consistent with temp?
Re: Bullets were fine, now keyholing after 150 rounds?
You can ruin a barrel brushing too much. I use a plastic 270 brush to hold patches neatly for cleaning the 30 cals and my 30 cal plastic brush for cleaning my 8mm's.
I don't think you've killed it yet, but I'd cut that brushing out for the most part. Read through this article to get a better idea of what I'm getting at. I thought I was being negligent because I rarely cleaned my rifles unless I shot corrosive ammo through something. Now I don't feel so bad.
http://www.6mmbr.com/borebrushing.html
You can ruin a barrel brushing too much. I use a plastic 270 brush to hold patches neatly for cleaning the 30 cals and my 30 cal plastic brush for cleaning my 8mm's.
I don't think you've killed it yet, but I'd cut that brushing out for the most part. Read through this article to get a better idea of what I'm getting at. I thought I was being negligent because I rarely cleaned my rifles unless I shot corrosive ammo through something. Now I don't feel so bad.
http://www.6mmbr.com/borebrushing.html
Re: Bullets were fine, now keyholing after 150 rounds?
At what distance does the bullet appear to begin to become unstable?
At what distance does the bullet appear to begin to become unstable?
Re: Bullets were fine, now keyholing after 150 rounds?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tyler Kemp</div><div class="ubbcode-body">I don't buy that you need even close to a 1 in 8" twist, I shot them out of my 1 in 10" 6mm Ackley and they were fine to to 600 yards. </div></div>
Then what's causing the keyholing? Too much twist!? You are also probably pushing them a lot faster- in the 3150 to 3250 range. What's your velocity on the 6mm AI.
RN182- what powder charges are you are trying?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tyler Kemp</div><div class="ubbcode-body">I don't buy that you need even close to a 1 in 8" twist, I shot them out of my 1 in 10" 6mm Ackley and they were fine to to 600 yards. </div></div>
Then what's causing the keyholing? Too much twist!? You are also probably pushing them a lot faster- in the 3150 to 3250 range. What's your velocity on the 6mm AI.
RN182- what powder charges are you are trying?
Re: Bullets were fine, now keyholing after 150 rounds?
Sterling Shooter: This was at very close range, like about 20-25 yards as I wanted to make sure I'd be on paper further down range. Where I have been shooting is about 80 yards they were fine to there in the previous trips.
Sterling Shooter: This was at very close range, like about 20-25 yards as I wanted to make sure I'd be on paper further down range. Where I have been shooting is about 80 yards they were fine to there in the previous trips.
Re: Bullets were fine, now keyholing after 150 rounds?
I shoot them in the same gun and Chad is on the money. The whole brushing thing is an ongoing debate that will never be settled. I shoot a bunch of benchrest and I clean including brushing every 15 to 20 rounds which is after every relay. I have thousands of rounds through barrels like this with no issues. Would they last longer if I didn't clean this way? I don't know and my smith doesn't want me to find out!!
I shoot them in the same gun and Chad is on the money. The whole brushing thing is an ongoing debate that will never be settled. I shoot a bunch of benchrest and I clean including brushing every 15 to 20 rounds which is after every relay. I have thousands of rounds through barrels like this with no issues. Would they last longer if I didn't clean this way? I don't know and my smith doesn't want me to find out!!
Re: Bullets were fine, now keyholing after 150 rounds?
Perhaps, it's damaged bullets, or damaged bore.
Perhaps, it's damaged bullets, or damaged bore.
Re: Bullets were fine, now keyholing after 150 rounds?
Yes, I've had this happen before. It's really pronounced in my 6ppc. It's a 1-14 twist and will not stabilize 69gr bullets below 75 degrees. I've experimented with this starting at 58 degrees. At this temp the bullets wouldn't hit the paper at 100 yards. As the temperature started to rise, yopu could actually watch each 5 shot string get better. I also alternated shooting 65 and 68 grain bullets at the same time I shot the 69's. The 65 and 68 bullets had no problems and shot bughole groups.
Anyway's, thought this might help.
Yes, I've had this happen before. It's really pronounced in my 6ppc. It's a 1-14 twist and will not stabilize 69gr bullets below 75 degrees. I've experimented with this starting at 58 degrees. At this temp the bullets wouldn't hit the paper at 100 yards. As the temperature started to rise, yopu could actually watch each 5 shot string get better. I also alternated shooting 65 and 68 grain bullets at the same time I shot the 69's. The 65 and 68 bullets had no problems and shot bughole groups.
Anyway's, thought this might help.
Re: Bullets were fine, now keyholing after 150 rounds?
FWIW...I believe that you are on the very low end velocity wise. Although Winchester brass usually has a slightly lower capacity than Federal, your case may be different. (pun intended) The AMAX is a long bullet and the 9 twist won't reliably stabilize it unless the velocity is up. Also, "starting loads" as listed in the manuals are very conservative. Work up toward the max listed. Spend a bit on the chrony. You will save money in the end by knowing what is really going on. JMHO
FWIW...I believe that you are on the very low end velocity wise. Although Winchester brass usually has a slightly lower capacity than Federal, your case may be different. (pun intended) The AMAX is a long bullet and the 9 twist won't reliably stabilize it unless the velocity is up. Also, "starting loads" as listed in the manuals are very conservative. Work up toward the max listed. Spend a bit on the chrony. You will save money in the end by knowing what is really going on. JMHO
Re: Bullets were fine, now keyholing after 150 rounds?
Thanks for all the info guys. Starting loads were 46 grs, at 48 grs theres no keyholing at all (although accuracy still sucks at about 4.5" at 80 yards. Switched to IMR4350, no keyholing at all and accuracy is much much better. Worst group 1.4" at 80 yards, best was a little less than 0.5". Think I will give up on Retumbo for the time being. Thanks again everyone for the free education!
Thanks for all the info guys. Starting loads were 46 grs, at 48 grs theres no keyholing at all (although accuracy still sucks at about 4.5" at 80 yards. Switched to IMR4350, no keyholing at all and accuracy is much much better. Worst group 1.4" at 80 yards, best was a little less than 0.5". Think I will give up on Retumbo for the time being. Thanks again everyone for the free education!
Re: Bullets were fine, now keyholing after 150 rounds?
Check you bbl. crown for damage.
Try FACTORY ammo.
How long have you been shooting??
Respectfully,
LG
Check you bbl. crown for damage.
Try FACTORY ammo.
How long have you been shooting??
Respectfully,
LG
Re: Bullets were fine, now keyholing after 150 rounds?
Lumpy: The crown doesn't look damaged to my untrained eye. One box of factory ammo was shot in this gun, 80 grain Remingtons and they seemed to shoot very well but it was very windy and nobody shot more than 2 rounds at 100 yards (there were alot of people who wanted a turn ;p). I have 'shot' quite a bit but until I got my .243 it was shotguns for hunting and .22's for fun, and no reloading or shooting for groups, so you could say I've only *REALLY* been shooting for a month or so. Since then I'm shooting a couple of nights a week for as long as I can stand the mosquitos, usually 10-20 rounds. Anyway, I think the guys were right about the velocity needing to be up a little to get enough spin, just seemed strange that it was fine the first few times. Anyway, once I get a chrony I will try to make the retumbo work, for fun, but for now the IMR4350 is working (my first 0.5" 3 shot group at 80 yards!!) so I'm going to try to dial that in as best I can.
Lumpy: The crown doesn't look damaged to my untrained eye. One box of factory ammo was shot in this gun, 80 grain Remingtons and they seemed to shoot very well but it was very windy and nobody shot more than 2 rounds at 100 yards (there were alot of people who wanted a turn ;p). I have 'shot' quite a bit but until I got my .243 it was shotguns for hunting and .22's for fun, and no reloading or shooting for groups, so you could say I've only *REALLY* been shooting for a month or so. Since then I'm shooting a couple of nights a week for as long as I can stand the mosquitos, usually 10-20 rounds. Anyway, I think the guys were right about the velocity needing to be up a little to get enough spin, just seemed strange that it was fine the first few times. Anyway, once I get a chrony I will try to make the retumbo work, for fun, but for now the IMR4350 is working (my first 0.5" 3 shot group at 80 yards!!) so I'm going to try to dial that in as best I can.
Re: Bullets were fine, now keyholing after 150 rounds?
I'm showing 49 grains of Retumbo as a max charge. So, you still have some room to increase your charge weight.
IMR 4350 is a good powder, but you might getr more velocity with a powder burn rate between Retumbo and 4350.
I'm showing 49 grains of Retumbo as a max charge. So, you still have some room to increase your charge weight.
IMR 4350 is a good powder, but you might getr more velocity with a powder burn rate between Retumbo and 4350.
Re: Bullets were fine, now keyholing after 150 rounds?
Thanks for the input Chad, once I get a chronograph I will experiment with powders for best velocity.
Thanks for the input Chad, once I get a chronograph I will experiment with powders for best velocity.
