6.5-06AI pressure issues

[theirontexan]

I recently had a 6.5-06 AI built by pac-nor. When loading for this rifle, I ran into the fact that it was showing pressure signs far before I would imagine it should. I was half a grain under the suggested max for the non ackley improved version of the case, and I had a flattened primer, and ejector markings on the back of the casing and the primer was formed around the firing pin.

The only thing I would consider different from any other cartridge I've loaded is that the throat on this rifle is really short. I loaded it with the bullet touching the lands, and the OAL was 3.255 as opposed to nosler's 3.440 with a 130 grain accubond.

Also, would it be possible that I am running into high pressure because the bullets are so heavy for caliber as opposed to a 25-06 or a .270?

I've never reloaded for a rifle that showed pressure signs this early, and it bothers me to a rather high degree. I'm loading IMR4350, do I need to change powder?

I'm lost, and I'm especially worried because I want to bump up to a 140 grain bullet (got the accubonds at the local gunshop, it was what they had, and I wanted to go shoot my new gun.) But if I do that, will it make my pressure issue worse?

 

[BountyHunter]

I built a 6.5-06AI recently and planned on shooting the Berger 130s.

I would think 4350 is not a good match for that case.

I put out a data call for anyone working with RL26 as it has a reputation for giving very good MV and low pressures. Some are pushing way higher than thought.

I have not had the time to load develop yet, I have a die being modified for bushings by JLC.

I would suggest giving RL 26 a try, and just work up from standard 6.5-06 load data.

The other powder that got high marks was N-165. Several had high praise for it.

 

[jakelly]

I'd give H4831sc and H1000 a shot.

 

[stomp442]

H4831 and Retumbo have always worked best for me in that cartridge. I am currently running 59 grains of H4831 and a CCI magnum primer for a velocity of 3180 in a 26" 9 twist shaw barrel. Start low and work up.

 

[theirontexan]

I've noticed several people using magnum or "hot" primers. Is this common with the slow burning powders like RL26, RL22, Retumbo, H1000 and H4831?

 

[R.Morehouse]

I use RL22 in my 6.5-06 Baer with Fed. GM210M primers and 141 VLD's from Bob C. out of a 30" barrel getting 3150fps....This is a 1000yd benchrest set-up. RL25 will work well also. gun)..........................

 

[stomp442]

I've noticed several people using magnum or "hot" primers. Is this common with the slow burning powders like RL26, RL22, Retumbo, H1000 and H4831?

It worked for me. My E.S. & S.D. numbers were horrible until I switched to a magnum primer and that brought everything together nicely.

 

[MudRunner2005]

Seating the bullet into the lands can, and will cause excess pressure and pressure spikes, which can sometimes appear to be early pressure signs and can also cause heavy bolt lift, cratered primers, ejector marks, etc...

Try seating the bullet away from the lands some (.015-.025") to see if the pressure signs subside or go away completely. I can't guarantee it will help, but it's worth trying.

Another thing, OAL is not a good way to judge your cartridges, as every brand and model bullet all have different shaped and length Ogives and maplats (the tip of the bullet). Measuring your cartridges from base-to-Ogive with a comparator tool is a much more accurate way to measure cartridge length, and when you use the comparator in conjunction with a cartridge OAL gauge, that is the most accurate way to measure your distance to the lands with a particular bullet.

 

[theirontexan]

Seating the bullet into the lands can, and will cause excess pressure and pressure spikes, which can sometimes appear to be early pressure signs and can also cause heavy bolt lift, cratered primers, ejector marks, etc...

Try seating the bullet away from the lands some (.015-.025") to see if the pressure signs subside or go away completely. I can't guarantee it will help, but it's worth trying.

Another thing, OAL is not a good way to judge your cartridges, as every brand and model bullet all have different shaped and length Ogives and maplats (the tip of the bullet). Measuring your cartridges from base-to-Ogive with a comparator tool is a much more accurate way to measure cartridge length, and when you use the comparator in conjunction with a cartridge OAL gauge, that is the most accurate way to measure your distance to the lands with a particular bullet.

I did not know this. I was taught to just put it where the bullet was touching the lands, and have never run into this problem, or heard of it before. I'll adjust a few and give them another go.

I understand that OAL is not the best measure, and that you cannot compare different bullets when using OAL. However I can compare using OAL when using the exact same bullet, correct? Its what I have right now, and this month's budget for shooting was expended on components for my rifle to get it into hunting shape, and so that I can start fireforming brass.

What specific comparator tool would you suggest? Also, would it be worth it to invest in a micrometer style bullet seating die?

 

[Slick8]

Here's what Mudrunner is referring to. It's a great way to measure Base to Ogive of a loaded round. You simply attach the red anvil to a dial caliper and use the insert for your bullet diameter.

Hornady Lock-N-Load Bullet Comparator Basic Set 6 Inserts

I have Redding dies and recently bought a micrometer adjustable seating die and love it in my 7RM. It's not necessary but sure makes things nice.

I agree with the above, that running on the lands will show press signs sooner then if backed off. The reason is that being seated at or into the lands requires more force to start the bullet moving forward then if backed off of the lands.

I've had excellent results with running bergers from .018 to .050" off the lands. Here's a good read from Berger on the subject.

http://www.bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf

 

[FEENIX]

I did not know this. I was taught to just put it where the bullet was touching the lands, and have never run into this problem, or heard of it before. I'll adjust a few and give them another go.

Do you own a reloading manual? If not, I highly recommend getting one, they have tons of information, esp. on safety and makes an excellent reference manual as intended. Most of mine talks about pressure signs in relation to the rifling, for instance, pages 26 and 26 (sorry, not the best scan job but hopefully it gets the point across) of Hornady 9th ed ...

Hope you find the sweet and safe spot. Good luck and happy safe shooting/hunting.

 

[theirontexan]

Do you own a reloading manual? If not, I highly recommend getting one, they have tons of information, esp. on safety and makes an excellent reference manual as intended. Most of mine talks about pressure signs in relation to the rifling, for instance, pages 26 and 26 (sorry, not the best scan job but hopefully it gets the point across) of Hornady 9th ed ...

Hope you find the sweet and safe spot. Good luck and happy safe shooting/hunting.

Ok, I can see why thats going on then.

I've learned everything I know via being taught by 2 different people. I learned my basics from my grandfather, then my roommate's dad took me under his wing and I've been learning from him. I've never used a loading manual for anything but a reference for load data. Both of them set bullets touching the lands, so I considered it normal and never questioned it.

I've already backed off for my current hunting load. It shoots well enough I'm not worried about it for my current hunting purposes (grouped at 9/10 of an inch at 100 yards in an unbedded stock and the furthest I'll have to shoot this season will be 300, I can make that work), however starting at the first of Feb, I'm beginning the full load development for this rifle. I'll acquire a full reloading manual between now and then. And I'll acquire a gauge for my cartridges.

Thank yall for your help.

 

[RAT807]

[However I can compare using OAL when using the exact same bullet, correct?/I]

Sometimes, yes. I have seen as much as .025 difference in bullet base to ogive length in the same box of 100 bullets. I won't name the brand, but they do make high quality, not cheap bullets and I still use them. I just measure the ogive length of them all while sorting. Once you start measuring the ogive and OAL of your bullets, you will see they vary a good deal.