6.5 MM woes

[Rcmaveric]

Just needed to vent for a minute. Last year I bought a .260 Remington. I have been trying to get this thing to shoot for about a year. Tried the 6.5mm RCBS 140g SIL with no luck. Tried everything i could imagine. The nose was too fat and would force the seating depth so deep they fell into the case. That RCBS bullet also very long. My thought could have been the lead over pressuring before stabile speed was attained. Same result with NOE .266 Grendel Bullet. I thought nose sizing was the answer. Through nose sizing the bullets i have been able to get some positive results with Grendel, but not stellar groups. So that reaffirmed my hypotheses about pressures and stable speed on the RCB SIL bullet. Alas, the RCBS bullet was still a failure. I haven't given up and i kept the quest through trials and error and different idea. While perusing NOE, i found the had a Creedmoor bullet. I compared the .260 Remington to the Creedmoor and found the throats very similar. As in, only a few thousands of an inch difference. I thought this bullet would be the ticket. So, NOE had their sale and i drooled so hard the SWMBO gave me permission to get it. Beginning of the month i loaded up maybe about 200 test rounds. I also finaly rebuilt my Grendel after the accident and it has been acting up. So with high hopes, expectations and a few dreams i was off to the range yesterday. Well it was all epic failures.

260 Remington: I think i messed up the pressure calculations. I like to calculate the possible chamber pressures to figure out where to start the load test within the published load data. The powders used were Reloader 7, D060 (Accurate 5744 equavlent, load reduced to work up), H4895, and IMR 4198. Also while shooting i had few time the chamber was kind of harder to close. So maybe i was jamming them into the lands and spiking the pressures. So now i have about half the bullets left over. I crimped them slightly so i cant just seat them deeper. So know i need smoke a bullet and chamber it to see if i really am seating into the lands. Then i need to adjust the seating depth if needed. Pull all those bullets. Then adjust those charges and try again. Its a love hate. I love to shoot and this gun hates me. (After Thought: The Charges that should have been soft, had noticeably higher recoil that what was estimated)

6.5 Grendel: Been giving me a head ache aswell. The seating depth on this barrel was massively different that the old barrel. So i had to pull down all the old bullets. This time, out of 20 rounds, only one failed to go into full battery. I fixed the feeding issues from last time by polishing the M4 feed ramps. I got excited when i pulled the trigger and it cycled. I ran a whole mag and the bolt locked back. So now the problem is, its slam firing. Happened twice, it bust fired two rounds. That's a no-no at my range, but i don't thing anyone but me noticed. So for this gun i need to seat just another .001 deeper and then clean my seating die. My thought is that either the gun is just marginaly being gassed that it didn't lock the hammer back and it slam fired. So i either need more powder or i need to open my gas port. I am 90% sure the gas block is installed correctly. There is notch in the barrel for the set screw to rest in. This round was a tack driver in the old barrel. I stopped testing because of the double fires. I didn't want to get into trouble for double fires.

Now the heart break: My target looked like a shot gun pattern. Target was 50 yards. I could not make out anything .260 or Grendel. Some of the .260 bullets key holed a few times. So they could have over pressured and slumped or didn't stabilize. I did run the bullets stability check and my .260 Rem bullets should stabilize just fine at 1650 fps, twist 1 in 8, bullet is 1.11 inches long, 140g, and .266 diameter. I thought i leaded the .260 Rem Barrel, but its a little grimy. I don't see any leading. just some bad antimony wash around the muzzle. I thought i leaded the 260 bad because when i tried the marginaly decent load it still missed bad.

Then to add insult to injury. I pulled my .270 out that is normally my therapy. My normal MOA groups tripled. Though, that one is tuned in cooler weather. I did try a different lube, but i don't think a lube will blow a group that bad. It was also 90*+ out and humidity was 90%. Maybe it was a combinations of the wheather, different lube, and heat that opened the group. I couldn't help but think droping the charge 5% would fix it. A storm came in and i had to swim out and get my target then swim to my truck.

Grumbling over. Time to hit the drawing board. I know what i need to do, i just needed to vent for a bit and re-find my determination. Nothing is proven until its repeatable. Thinks for the ears and all opinions and ideas are welcome.

[nicholst55]

Definitely troubleshoot your AR-15 and determine why it's doubling and correct that. If it's a mechanical problem, that can get you into trouble with the BATF if you don't correct it. I would personally look for a mechanical problem first. How does your .260 shoot with J-words? You didn't mention that, and if you haven't yet tried it with factory ammo or jacketed handloads, I certainly would recommend that to determine it's baseline accuracy potential.

[popper]

Better check HS on the 65, different chamber and shoulder in wrong place.

[MT Chambers]

You may have to get a mold made to your specs, I have many molds that just don't work with some rifles, the bore riding portion is too wide or there is no bore riding portion which happens on some LBT molds as Veral does not believe in "bore riding bullets", so you have to seat them so deep that over half the bullet is below the case shoulder inside. Put the current mold aside and try it later in a dif. chamber, eventually you'll find a perfect match.

[Rcmaveric]

I haven't tried Jacketed bullets in the new 6.5 Grendel barrel. I know the .260 Rem can shoot an MOA group with Hornady Jacketed bullets without much effort.

I took the AR apart when i got home. I checked the trigger group and bolt. I was unable to identify a mechanical problem.

[Calamity Jake]

What primers are you using in that 6.5 Grendel? The firing pin is free floating, a too soft primer cup like federal will slam fire
in and ar type application.
I use CCI and sometimes WW.

[Rcmaveric]

What primers are you using in that 6.5 Grendel? The firing pin is free floating, a too soft primer cup like federal will slam fire
in and ar type application.
I use CCI and sometimes WW.

I use Winchester Large Rifle in the converted 7.62x39 cases.

[Rcmaveric]

Well now. Was following Popers advice and checking headspace. Head space on the .260 Rem checked good. Disassembled the AR. And was playing the trigger and hammer. Well lets give this an op check and a better visuall while i have it apart. So i pulled the trigger while hold ing the hammer. Sear released nice and crisp. Held the trigger and cycled the hammer. Secondary sear engaged ( the hook one that prevents burst fire). Let go of the hammer and the released the trigger. The the secondary sear released, the hammer released and got me good in the thumb. Well, thats not how the trigger is supposed to work. Did a few more times to verify. And sure as I'll be if it wasnt consistently.... binary? Would be the better legal term. Took the trigger group apart and the only problems were the two pins were bent. Thought no way that causes it. So i dug out two metal pins of the aproximate diameter to hold the triger group in. Well guess what? The trigger acts right now. Secondary sear catches the hammer like it should if you hold the trigger and when released tue primary sear catches it.

Pin on top is badly bent. Most noticeable when you roll it. Pin on bottom looks fine but i will replace to be safe.

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[Rcmaveric]

Just finished checking head space on my Grendel it checks good as well. Just need to tweak that seating depth for both.

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[JMax]

I have a Norwegian Krag in 6.5 x 55 that gave me heartburn for a year with a number of 6.5 Swede molds because the throat is shorter than Swedish rifles. I worked with Swede owner of NOE and got his 145 gr hunter that I size to .268. Now I can seat the bullet to just touch the lands and the gas check is still in the case neck.

I also found that RPM is a big deal due to the rapid twist rate so my cast loads are limited to just under 1400ft/sec. I shoot with iron sights and shoot clay pigeons at 100 yards with abandon with this rifle and bullet.

[blue32]

OP, thanks for posting the update. I decided to put the 260 on the back burner... yet again. That's a bummer with the NOE bullets. I've started to wonder if my 1:8 twist is going to make cast a no-go with mine. I also get great accuracy with jacketed loads.

[Rcmaveric]

OP, thanks for posting the update. I decided to put the 260 on the back burner... yet again. That's a bummer with the NOE bullets. I've started to wonder if my 1:8 twist is going to make cast a no-go with mine. I also get great accuracy with jacketed loads.

For the 260: I honestly think i just seat out too far. Seating into the lands will cause a pressure spike. I also think i over estimated the begining charges also. All the loads i used were published. They were just big jumps beteen min and max. I estimated 25k to 38k psi zone for the tests. But my calibrated should says that wasnt 25k psi on the first shot. I should have started at the min charge and worked my way up until the groups blow open. Thats what i normaly do, but i was.trying to be a nerd with QL and cut corners and save components and time. Looks like i tripple my time and frustration.

I dont like how the gas check is below the case neck. But isnt no where near as bad as the other bullets i have on hand. The creedmoore bullet is just .01 bellow the case neck. I here 50/50 tales about bad or wives tales. I will just let my taget tell me.

That 1:8 is fast. If i can do it right i see 2000 fps as should be attainable. My goal is minimum of 1850 fps with moa accurracy.



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[Yodogsandman]

Try a low velocity/low pressure charge to see if it improves. I normally test all new molds at low velocity first with like 10gr of Unique. If you cant make it work at low velocity, it wont work at all.

[Rcmaveric]

Try a low velocity/low pressure charge to see if it improves. I normally test all new molds at low velocity first with like 10gr of Unique. If you cant make it work at low velocity, it wont work at all.

I don't have any Unique. I have some Red Dot, Blue Dot, Tight Group, Clays and 2400.

[sigep1764]

The 260 is based on the 08 case, right? 10 or 12 grains of red dot ought to be pretty mild.

[Larry Gibson]

That 1:8 is fast. If i can do it right i see 2000 fps as should be attainable. My goal is minimum of 1850 fps with moa accurracy.

An admirable goal. Yes it can be done but not with the long nose bore riders or the powders you're using. Suggest you "search" and read the trials and tribulation of shooting HV cast in the 6.5 Swede. Pay close attention to the substantiated accuracy and velocity loads that achieved actual accuracy at HV. What was/is applicable to the fast twist 6.5 Swede is applicable to you fast twist 6.5s also. I had a 6.5-308 (basically the same as a 260 Rem) with a 9" twist also. It never shot cast well over 1800 fps unless the 266455 or Kurtz bullets were used.

[bruce drake]

Agree with EVERYTHING that Larry just posted.

I found that with my 6.5 Grendel (AR15) rifle liked a cast lead 100gr bullet from Lyman that I believe is discontinued (266305). I also use reformed 7.62x39 brass as my barrel is the original Type 1 chamber design which uses a standard 7.62x39 AR bolt. If I ever rebarrel it to the newer Type II chamber, I'll replace the bolt for the deeper bolt face Type II bolt also. I think you need to look at why that hammer assembly pin bent and also to ensure the lower receiver pinhole didn't get wallowed out by the bending pin. You might have to switch to a drop-in trigger assembly with pins that are held in place by external-headed anti-lock pins if the pin hole is now out of round also.

The 140gr 266469 bullet mold is my go to at 1600fps in my Swedish 6.5x55 rifle and its tight twist. My 260 Rem is a rechambered T38 Arisaka and its metford rifling prefers a 280468 cast bullet sized down to .269" but its a 115gr bullet and lighter than what you are using I believe. I use a standard 266469 140gr bullet PCed up and sized to .268" for use in my standard 6.5x50mm T38 Arisaka.

I recently acquired a Lyman 266455 off Evil-Bay that I intend to test out in my 6.5 Creedmoor AR10 rifle later this year also.

[Rcmaveric]

Mr. Gibson thanks for the tips. I just ran a search for HV 6.5X55 HV pulled up several articles and i will read them now. I use 6.5x55 load data sometimes and reduce it. I never considered 2000 fps as HV, I always thought 2200 FPS and above as HV. The NOE 140-FN isn't a long nose bore rider design like the NOE Grendel bullet and RCBS 6.5-140-SIL. I figure if i can get my old Grendel shooting at 2000 FPS and my .270 Win @ 2000 fps then i should be able to get the 260 shooting between 1800-2000. For estimating bullet drop, i will confess that my skill at that is lacking. I like to Zero my riffles at 100 then use the ballistic reticle. At 1650 FPS the drop for the .270 was too much. But at 1800-2000 fps, i can easily hit targets out 200 yards.

Mr. Drake, my old Grendel upper loved the NOE Grendel bullet and it shot very accurately at 2000 fps. I had an accident with that upper and had to build a new one. I couldn't afford to use Aeroprecision and Blackwhole Weaponry (Polygonal Rifling) again. I caught a sale at midway for a new Grendel barrel and Type II bolt and upper for 300.00. Its a Midway name brand and i don't know who makes it. The reviews are good though and the myth/rumor is that Saturn (did i spell that right?) makes them. Its not a custom high grade barrel but i am hoping to be able to atleast hit 1850 FPS. I have fixed the feeding issues in the new gun. I replaced those pins and they are nice and tight. I performed a trigger functional test and safety works, holding the trigger while cocking the hammer and releasing the trigger works now. Everything appears to hold as it should with no slop or play. I feel confident with it and just needs a live fire test now. The new barrel is 5R rifling instead of Polygonal. I only ever tried the NOE 266-125-RF (Grendel bullet) it works like a champ previously.

Thanks for the tips and home work gentlemen. I have brass prepped and ready now to reload for the range tomorrow. I will just try some generic military riffle loads from CE Harris's article that are adjusted in QL for the target velocities. Those loads are for 30 cals and normal only need a small reduction for 6.5 cals.

I just need to quadruple check my notes and seating depths. Hopefully i will have some positive news from tommorrows shooting at 50 yards. I honestly do think it was seating depth causing pressure spikes and starting to high on the charges. That's what heppended in my .270 Win. I know each gun is rule into self though. I am trying modest charges now and if they work i will know where to go next.

[RobS]

I was reading your OP and yes lube can be an issue with 90 degree day and 90% humidity. This is not the easiest environment for a lube especially if an original load was established when the temps were much cooler. I am referencing the part where you were talking about your 270 cast boolit load not shooing well. Could also be an issue you are seeing with the 6.5 boolits too but wouldn't have a variable to compare with your current situation.

[Rcmaveric]

Thanks everyone for reminding me not to be discouraged and to stick to the basics. Today was the closest taste of success the .260 Rem has ever given me. I just adjusted the seating depths on the Grendel and .260. Dropped the charges down to emulate CE Harris loads for military riffles. I now have a starting point on both rifles to tune from.

Leave it to NOE to make the 6.5m molds i needed. I shouldnt have feered or gotten exasperated.

All targets were 50 yards. All lube was SL68B. Temps were humid and in the 90s.

One thing I did note for the .260, if you convert it from .308 then it may take a few fire forms and neck turn to make it chamber good. If you converted it from .243 then it doesnt need a neck turn and only takes one fire if that. The .243 converted brass will feed like butter. The .308 may take a few fireforms and anneals to feed like butter.

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