260AI with 140gr. bullet is too slow?
- Thread starter Billch
- Start date
CaptainMal
Silver $$ Contributor
Dread this reply but I'm gonna do it anyhow.
I had one built with a Krieger 8 twist 5R on a Remington action. Friend got all excited and he did the same but on a Kelby or something like that. Another friend got excited and did one on a Savage. ALL THREE ARE BUMMERS.
Just hit the 500 rd. testing mark today. SLOW for one thing but poor accuracy seems to be another issue if you try and speed it up. I/we have tried a variety of powders. Right now I'm playing with 4831SC and Reloader 22. Was told that Quicikload said the ONLY powder to use with 140's is MRP.
You cannot get MRP. Norma makes it with "unobtanium". Reloader 22 is the same burning rate and my initial tests today do show I can get sub MOA groups WITHOUT those cursed flyers using it and MAG primers.
My gun was built with a 26" barrel for long range hunting. Really upset is the friend who used a 30" bbl and expensive action and stock to use it for target. No accuracy but we do make pretty cases. He uses Lapua along with match 308 brass but his efforts there have not been successful. The third is a hunting rifle and the guy lost interest and don't know his current status.
My thoughts are it's a loser cartridge yet I hope to get a consistant 1/2 MOA hunting rifle out of it before wearing out the barrel and my patience testing.
MRP and Reloader 22 may be some help to you.
I had one built with a Krieger 8 twist 5R on a Remington action. Friend got all excited and he did the same but on a Kelby or something like that. Another friend got excited and did one on a Savage. ALL THREE ARE BUMMERS.
Just hit the 500 rd. testing mark today. SLOW for one thing but poor accuracy seems to be another issue if you try and speed it up. I/we have tried a variety of powders. Right now I'm playing with 4831SC and Reloader 22. Was told that Quicikload said the ONLY powder to use with 140's is MRP.
You cannot get MRP. Norma makes it with "unobtanium". Reloader 22 is the same burning rate and my initial tests today do show I can get sub MOA groups WITHOUT those cursed flyers using it and MAG primers.
My gun was built with a 26" barrel for long range hunting. Really upset is the friend who used a 30" bbl and expensive action and stock to use it for target. No accuracy but we do make pretty cases. He uses Lapua along with match 308 brass but his efforts there have not been successful. The third is a hunting rifle and the guy lost interest and don't know his current status.
My thoughts are it's a loser cartridge yet I hope to get a consistant 1/2 MOA hunting rifle out of it before wearing out the barrel and my patience testing.
MRP and Reloader 22 may be some help to you.
Your velocity IS low, and only some of it is too short of a barrel for the cartridge.
But I shoot a 6.5wssm imp which holds the same exact capacity as a 260AI. My accuracy node is 3040fps using 47.4gr IMR4350 with 140gr VLDs from a 28" barrel. I've also run this brass up to 3200fps+ before FL sizing would be required(my max).
At 3040fps FL sizing has never been needed(I don't).
I wonder if your chrono is correct. How far from the muzzle, and are you adjusting read MV to actual?
Consider how much more capacity you have to work with over a puny 6.5x47. You should easily be able to go 3000fps+.
But I shoot a 6.5wssm imp which holds the same exact capacity as a 260AI. My accuracy node is 3040fps using 47.4gr IMR4350 with 140gr VLDs from a 28" barrel. I've also run this brass up to 3200fps+ before FL sizing would be required(my max).
At 3040fps FL sizing has never been needed(I don't).
I wonder if your chrono is correct. How far from the muzzle, and are you adjusting read MV to actual?
Consider how much more capacity you have to work with over a puny 6.5x47. You should easily be able to go 3000fps+.
OP, try the amax, I have found it is the fastest bullet I have used. I have no idea why, but it was 50fps faster than both the 140 horndady HPBT and 142 SMK with the exact same charge. But I still think you either have a chrono issue or just a slow barrel. It Happens.
Cliffe, I agree with your assessment, however, that was with 4831SC, he was using H4350. Also, my H4350 load, while a modest 2800 fps, was only using 42 grains. He was using 46.3grs, so the barrel length alone probably wouldn't explain the velocity disparity. I would imagine that getting to 2950 wouldn't be too difficult.
Boiler,, it was a compressed load forsure, but I never had any issues with COAL. I was using a Redding FL die so I had a little extra neck tension. I have since switched dies for about .002 of tension. But, I have stopped using H4831SC. I know Terry Cross was using 48.5grains of H4831SC in his 260 ackley for around 2920 with a 26inch tube. I am not going to waste my time with Lapua 260 brass anymore though, prepped Win 7-08 brass has been just as consistent for me after some prep.
Also, my load going 2900ish was incredibly accurate, and would maintain .2s to .3s. I have a handful of groups in the .1s. That was not the norm though. Also, I cleaned some strings at a 600 yard Fclass match with that load.
Justin
Cliffe, I agree with your assessment, however, that was with 4831SC, he was using H4350. Also, my H4350 load, while a modest 2800 fps, was only using 42 grains. He was using 46.3grs, so the barrel length alone probably wouldn't explain the velocity disparity. I would imagine that getting to 2950 wouldn't be too difficult.
Boiler,, it was a compressed load forsure, but I never had any issues with COAL. I was using a Redding FL die so I had a little extra neck tension. I have since switched dies for about .002 of tension. But, I have stopped using H4831SC. I know Terry Cross was using 48.5grains of H4831SC in his 260 ackley for around 2920 with a 26inch tube. I am not going to waste my time with Lapua 260 brass anymore though, prepped Win 7-08 brass has been just as consistent for me after some prep.
Also, my load going 2900ish was incredibly accurate, and would maintain .2s to .3s. I have a handful of groups in the .1s. That was not the norm though. Also, I cleaned some strings at a 600 yard Fclass match with that load.
Justin
I have a 260AI and shoot 140gn berger VLD exclusively. i can share my experiences in summary as I have been through multiple iterations of load development and yes I also have quick load. Some of these powders are the adi powders commonly found in NZ and Aussie. They all have USA based numbers as well ie: 2208 is varget.
I use rem 260 cases which I fire form using the cream of wheat method. CCI bench rest primers. My rifle is built on a short action with a 26" truflite match barrel. This rifle is used primarily for long range hunting to 800yds.
My objective is to run the 140gr vld accurately at about 2950fps mv.
ADI2208 - too much pressure before speed with 140gn pills
ADI2209 - better than 2208 and you should achieve 2800fps easy enough. Be aware you will be at the top end of pressure and there will be a fine line between acceptable and not
RL17 - I was unable to maintain consistent accuracy with the little bit of trying that i did so discontinued this
ADI2217 - I was unable to get sufficient powder in the case to give velocitiy required
ADI2213sc - highly accurate repeatable load (low ES) - velocity struggled with volume to get much past 2400fps
VV N560 - simply put - the best. Low pressure, temp stable, (I use 50.1gn for 2960fps with VLD's and 50.6 for 3020fps if I really want to be ambitious). ES is great, case life is great and I haven't noticed any difficulty on the chargemaster
cheers from down under in NZ
I use rem 260 cases which I fire form using the cream of wheat method. CCI bench rest primers. My rifle is built on a short action with a 26" truflite match barrel. This rifle is used primarily for long range hunting to 800yds.
My objective is to run the 140gr vld accurately at about 2950fps mv.
ADI2208 - too much pressure before speed with 140gn pills
ADI2209 - better than 2208 and you should achieve 2800fps easy enough. Be aware you will be at the top end of pressure and there will be a fine line between acceptable and not
RL17 - I was unable to maintain consistent accuracy with the little bit of trying that i did so discontinued this
ADI2217 - I was unable to get sufficient powder in the case to give velocitiy required
ADI2213sc - highly accurate repeatable load (low ES) - velocity struggled with volume to get much past 2400fps
VV N560 - simply put - the best. Low pressure, temp stable, (I use 50.1gn for 2960fps with VLD's and 50.6 for 3020fps if I really want to be ambitious). ES is great, case life is great and I haven't noticed any difficulty on the chargemaster
cheers from down under in NZ
Bilch, I noticed when you did your chrono testing the temp was 55F, at 75F you should gain another 40-45 FPS, I have found the Rem cases have 2 grain greater capacity over the lapua cases, Rel 17 should give you another 30 FPS velocity gain over the Hodgdon powders, on my 260 which previously was a 308 I had to have the firing pin hole bushed to 0060 thou and the firing pin reduced in size to 0058 thou to stop the primers cratering and piercing, I used to use 139gr lapua scenars when it was a 30 inch barrel, now I have had it shortened to 26 inches I use the 123gr scenars with no loss of accuracy and the lighter bullet makes up for shorter barrel, great caliber caliber
Regards, dooley
Regards, dooley
I played with the 260 AL my powder of choice was MRP 2 RL22 was good also
Good Shooting Larry
Good Shooting Larry
For my hunting rifle, in Straight .260, Rel. 17 gives me around 85fps faster fps then H4831 with 130 gr. hunting VLDS. Accurate and single digit. SD Your throat seems alittle long, but try them out. With the 130s start conservative at like 43 gr.s and work up. You maybe surprised. My gun has a 30" barrel , but you should get a 130. very close to 3000 Fps.
I'm a little surprised to see this thread brought back from the dead.
As an update, I've replaced the barrel with a 30" Bartlein 8.5 twist. I haven't had a chance to do much with it. It is chambered with the same reamer as my shorter barrel.
I did some work with RL-17 in the 25.5 inch barrel last summer. This wasn't all that bad accuracy wise. I may very well end up with a useable load close to this.
***Keep in mind these loads are for my rifle and very well could be very dangerous if you try anything close in your rifle.***
Chrono results:
123gr. MK
Seating @ 2.945
46.3gr. RL-17
Fed. 215M
Lapua .260 brass, formed
Str. 1
Av. 3147.6
SD 5.3
ES 13
I also went to the top with some Ramshot Hunter and the Berger 140 LR. The accuracy for this was less than acceptable. At least I know where the top is now. I also shot a string at 48.5gr. of Hunter. That was to hot.
140 HPBT-LR
Seating @ 3.065
48.3gr. Hunter
Fed. 215M
Lapua .260 brass, formed
Str. 2
Av. 2969.8
ES 21
SD 9
This last week I've been getting brass ready to reload, pretty much starting over as far as load development. I'm more confident with the 30 inch tube.
B
As an update, I've replaced the barrel with a 30" Bartlein 8.5 twist. I haven't had a chance to do much with it. It is chambered with the same reamer as my shorter barrel.
I did some work with RL-17 in the 25.5 inch barrel last summer. This wasn't all that bad accuracy wise. I may very well end up with a useable load close to this.
***Keep in mind these loads are for my rifle and very well could be very dangerous if you try anything close in your rifle.***
Chrono results:
123gr. MK
Seating @ 2.945
46.3gr. RL-17
Fed. 215M
Lapua .260 brass, formed
Str. 1
Av. 3147.6
SD 5.3
ES 13
I also went to the top with some Ramshot Hunter and the Berger 140 LR. The accuracy for this was less than acceptable. At least I know where the top is now. I also shot a string at 48.5gr. of Hunter. That was to hot.
140 HPBT-LR
Seating @ 3.065
48.3gr. Hunter
Fed. 215M
Lapua .260 brass, formed
Str. 2
Av. 2969.8
ES 21
SD 9
This last week I've been getting brass ready to reload, pretty much starting over as far as load development. I'm more confident with the 30 inch tube.
B
Bill, I've been somewhat disappointed with the velocities out of a 26" cut-rifled bbl chambered for the 6.5x55 AI. Accuracy goes downhill fast when I'm running loads that develop in excess of ~2840fps with 140s, no matter what powder I'm using, and caseheads show ejector swipe/flat primers. My practice was to use FF loads with very similar charges & powders that I'd used in a BAT 3LL with a 30" Bartlein hvy Palma bbl; this was obviously wrong, based on the pressure signs. The BAT's Bartlein easily produces over 2900fps with little or no sign of pressure, while the LA M700 action shows definite pressure signs using the same loads that work fine in the Bartlein. I'm pretty sure this is simply a matter of two different barrels having differences in bore/groove diameters, and maybe bore finish. Actually, I wasn't surprised at the lower velocity, as the 700's bbl is 4" shorter than the BAT's - it's the fact that the M700 shows so much more pressure than the BAT did, even with the same or very similar loads.
I guess what's most disappointing about the whole thing is that even though the 6.5x55AI has considerably more case capacity than the 6.5x47 Lapua, I'm not going to get much more than 50fps extra over what I get out of the Lapua with this particular 6.5x55 AI. IOW, the two 6.5x47s I'm still running are producing wonderful accuracy at those velocities with either 130VLDs or 140 LRBTs or Hybrids, while I've got to be very conservative with this 6.5x55 AI in order to get good accuracy. I may just 'retire' this 6.5mm bbl. and put a 280 AI bbl on the action instead.
I guess what's most disappointing about the whole thing is that even though the 6.5x55AI has considerably more case capacity than the 6.5x47 Lapua, I'm not going to get much more than 50fps extra over what I get out of the Lapua with this particular 6.5x55 AI. IOW, the two 6.5x47s I'm still running are producing wonderful accuracy at those velocities with either 130VLDs or 140 LRBTs or Hybrids, while I've got to be very conservative with this 6.5x55 AI in order to get good accuracy. I may just 'retire' this 6.5mm bbl. and put a 280 AI bbl on the action instead.
i hate to say it but you cant make a silk purse out of a sow's ear --
unless you are shooting off a bench and dont care about bbl length, there are a lot of cartridges that are more productive, better accurcy, and less expense in getting to shoot well, too many responses from those working to get the 260AI to preform
too many shooters with super results with other cases.
Bob
unless you are shooting off a bench and dont care about bbl length, there are a lot of cartridges that are more productive, better accurcy, and less expense in getting to shoot well, too many responses from those working to get the 260AI to preform
too many shooters with super results with other cases.
Bob
I have a couple of 6.5x 55 improved and like them. I am getting 2900 ft/sec with 130s out of a 20 inch barrel with 52 gr of N165 and I get just over 3000 ft/sec with 140 out of a 29" barrel using 52.8 gr of n165. just a note both my guns shoot well below 2750 or close to 2900.
Not sure about a 260 AI but the speed that was being quoted with powder being used seemed about right to me. I was a little surprise that a 260 AI dose not have more case capacity.
Not sure about a 260 AI but the speed that was being quoted with powder being used seemed about right to me. I was a little surprise that a 260 AI dose not have more case capacity.
If you want speed and accuracy Norma MRP is the best around 47.0 to 48.5 48. grains you must approach with caution with a 30'' barrel 47.3 gr 3050 was easy to reach.
i just put your figures in quick load and they didn't come out right i need to know the H2o of water capacity and bullet number and oal length
i just put your figures in quick load and they didn't come out right i need to know the H2o of water capacity and bullet number and oal length
I have 2 260 ai, one is quite old and was a pac-nor 3 groove pre-fit savage. The other is one of my current PRS series comp rifles. 2 different reamers with relativly short throats on each aprox .090" and .108"
Both barrels I use sorted remington brass, H4831sc, compressed loads, with 140 a-max in the savage and 140 hybreds in the other. Both give me velocities w 26" tubes at 2920-2930. In the second gun I had it as high as 2990, with no ejector marks but brought it down due to the shoots I go to can have hot temps and my load development is usually at or under 60 degrees.
accuracy with both rifles has been outstanding, LR groups in good conditions are typically 1/2 moa or less. I have loaded some remmy brass 6-7 times and have not had issues with donuts, but then again I might not care enough to know if I have them or not.
Both barrels I use sorted remington brass, H4831sc, compressed loads, with 140 a-max in the savage and 140 hybreds in the other. Both give me velocities w 26" tubes at 2920-2930. In the second gun I had it as high as 2990, with no ejector marks but brought it down due to the shoots I go to can have hot temps and my load development is usually at or under 60 degrees.
accuracy with both rifles has been outstanding, LR groups in good conditions are typically 1/2 moa or less. I have loaded some remmy brass 6-7 times and have not had issues with donuts, but then again I might not care enough to know if I have them or not.
If it helps you my 30 inch Brux on my 260 AI shoots the 140 Berger at 2850 with 45.6 grains of H4350. It is capable of more speed but hit a sweet spot I could not leave!, Careul because I originally mistakenly wrote 50.6 of H4350!!!!!!!!!!!Hi all,
I may be worrying about nothing.
I've got a 260AI (6.5-08 Improved) that I'm trying to work up a load for. Its a Savage LRPV, closed top, repeater action in the factory HS Precision stock. The barrel is a 25.5 inch Brux 1-8 twist, large shank, heavy varmint contour. The chamber was cut with a PT&G reamer with a snug, .296 neck and a long freebore to accommodate 140gr. class bullets by seating them out ahead of the potential donut area at the neck/shoulder. I thought I new what I was doing when I spec'd this reamer out. I'm having second thoughts now. I'll be swapping this barrel into a single shot target action with an A-5 stock in the next couple of weeks.
I'm up to 46.2gr. of H4350 with a 140 gr. bullet and I'm still not getting the speed I think I should be getting. Hodgdon lists the 260 Rem. max at 44.5 of H4350 so I'm well above that. For reference, Hodgdon also list 46gr of H4350 as max for the 6.5-284. My BR-2 primers are looking a little flat but nothing abnormal. I've compared them to primers from my 43gr. RL-15 308 load and there isn't much difference. No ejector marks, hard extraction, or anything like that.
I did some more chrono testing a couple of days ago. These were all previously fire formed and fully prepped cases. The weather was overcast and about 55 F. The range alt. is around 1200 ft.
Berger 140gr. HPBT-LR
OAL 3.010 (2.300 to ogive)
46.2gr. H4350
Lapua brass
CCI BR-2
Av. 2863 fps., ES-11, SD-2
I've also given the 142gr. MK a go with about the same powder charge and gotten similar results.
Sierra 142gr. MatchKing
OAL 2.924 (2.319 to ogive)
46gr. H4350
Lapua brass
CCI BR-2
Two 5 shot strings, averaged.
Av. 2876 fps., ES-15, SD-8
One of the first bullets I tried was the Berger 140gr. VLD. I does pretty well but still not as fast as I wanted. A big drawback to this load is there isn't much more room for more powder. These are seated .020 into the lands.
Berger 140gr. Target VLD
OAL 3.020 (2.354 to ogive)
47.5gr. H4831sc
Lapua brass
CCI BR-2
Four 5 shot stings, averaged.
Av 2850 fps., ES-19, SD-6
I hesitate to invest in RL-17. I've mainly used it for fire forming. It blows the shoulder out nicely and provide for some pretty good groups to boot. I don't bother to chrono fire forming loads much. The extreme spreads are typically large. This load shoots fairly well dispite having a big jump to the lands.
Lapua 139gr. Scenar
OAL 2.850 (2.285 to ogive)
43.5gr. RL-17
Lapua brass
CCI BR-2
Two 5 shot strings, averaged.
Av. 2848 fps.ES-41, SD-14
I feel like I should be able to get more speed out of this setup, something in the low to mid 2900fps range. It seems like I'm having to use an awful lot of powder to get he speeds I'm getting. Am I overly concerned? Should I just say it is what it is and be happy with what I've got? I've checked in to getting QuickLoad to help me out, but being a Mac user, I'm out of luck there. I suspect my long seating depth is causing the low speeds. If thats the case, can I just keep adding more powder to get what I want? I feel like the pressures are still in the acceptable range. I fear I may have to have my reamer reground with a shorter freebore and rechamber. Bummer!
Any help I could get on this would be much appreciated. I'm not feeling all that good about this whole 260AI project right now. I probably should quit reading on the interweb about how everybodys stuff shoots better than mine
B
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