Update...Small pressure sign, ok to keep loading????

[Mikecr]

It doesn't help but this is why I never understood the popularity in 6.5x284.
It's performance often declared is no better than reached with a 260AI (running way less & faster powder). And a drop below 140gr bullets is better covered with a 6.5x47L.
You cannot viably run high enough pressures with the 6.5x284 case to match the performance (accuracy-wise & life-wise) of smaller/better 26cal cartridges.
You get into the gun building aspects with a length of cartridge, that is in excess of needed. A shorter action could have meant longer barrel for same length gun. A smaller diameter case means more barrel steel around the chamber. Less powder means longer accurate barrel life.

I run a 26WSSM Imp with a 28" barrel. This is 260AI H20 capacity, but with brass twice as thick and a fitted chamber. I can push 140gr bullets faster than a 6.5x284 is capable of (without primers falling out in the action) before I need to FL size the cases. That's ~3350fps. My load of 47.4gr I4350 provides a mid node 3025fps, right at SAAMI max, and I don't have to size cases at all.

I only bring this up to get folks considering how different things can be with better planning. You might as well assume up front that load development will take you to best overall -near SAAMI max. Possibly past it. If your chosen cartridge is too big, you'll battle to get the accuracy you want at lower pressures, and battle to keep your brass and barrels alive at higher pressures. Which connects back to this thread..

 

[twister]

try the non magnum primer and you will basically be shooting my load

 

[Jeffrthehunter]

The Berger load data lists the following. Looks like you are within one tenth of a grain from max load. https://bergerbullets.com/pdf/6.5-284-Norma.pdf
Seems your concern is reducing the charge weight down results in a greater ES. Why not run the ballistic calculations and determine the difference in bullet drop you would experience between 3100 f/s vs 3120 f/s? I may be missing something here but if your ES of 20 results in a variance in bullet drop of 1 inch at 500 yards, is that something you can accept in return for alleviating pressure issues?

When I was speaking of 20 ES that was during a ladder test shooting 5 shots. I have ran several combos (lots of testing) through this gun and found that loads with higher ES (20 round velocity test gives me a 30-40 ES) will shoot 1 moa or larger at 850 yards. I found through testing that 53.4 to 53.6 gives me .5 moa and very low ES, this is a first for this gun. So I was thinking I could go out a confirm drop at 800 yards and get through deer season ( I hunt a couple different states). After which I will spend some more time finding a better load at less pressure. Based on some of the comments this is a bad idea.... Yes I could go with a lighter load and stay restricted to 500 yards but that's not what I wanted out of this rifle. I also posted this thread so I could learn more about pressure issues, I always want to learn.

 

[cjl2010]

Doesn't sound like you have a lot of confidence or time behind your rifle with any of the loads mentioned. Might be best to keep it at that 500 range for this hunt anyways.

 

[wonderman4]

The reason you are getting pressure signs with fire formed brass only is that brass does make a difference. Any time you change a component, you need to start load development all over cause things ain't the same.

For example: I normally load Winchester brass from the late 60s early 70s (I have gobs of it) for 30-06.

If I take Remington brass from the same era (I have gobs of it too), I have to load down 2-3 grains with the same powders to keep the same approximate velocities and keep the pressures approximately the same. If I load the same charge in the Remington brass as I do the Winchester brass, I get pressure signs galore.

This is just one example.

Going by this, I would think the internal volume of your fire formed brass is less than your other brass, whatever it may be.

 

[Jeffrthehunter]

The reason you are getting pressure signs with fire formed brass only is that brass does make a difference. Any time you change a component, you need to start load development all over cause things ain't the same.

For example: I normally load Winchester brass from the late 60s early 70s (I have gobs of it) for 30-06.

If I take Remington brass from the same era (I have gobs of it too), I have to load down 2-3 grains with the same powders to keep the same approximate velocities and keep the pressures approximately the same. If I load the same charge in the Remington brass as I do the Winchester brass, I get pressure signs galore.

This is just one example.

Going by this, I would think the internal volume of your fire formed brass is less than your other brass, whatever it may be.

Thanks for your thoughts. It is the same Norma brass but the slightly heavy bolt only shows on the second or third firing (when loading new I got a slower velocity and no hard bolt). Is it possibly that a little left over sizing lube could be part of the problem. After loading I just wipe rounds with paper towel.
Thanks Jeff

 

[bigedp51]

Resized cases fired in a semi-auto should be .003 to .005 smaller in diameter than their fired diameter. This allows the case to spring back from the chamber walls and extract reliably.
Is it possible you have a snug chamber and a fat resizing die. Measure the difference between the fired and resized diameter of the case at several points and also a new case diameter.

 

[338 dude]

Thanks for your thoughts. It is the same Norma brass but the slightly heavy bolt only shows on the second or third firing (when loading new I got a slower velocity and no hard bolt). Is it possibly that a little left over sizing lube could be part of the problem. After loading I just wipe rounds with paper towel.
Thanks Jeff

I've been shooting my 65x284 norma for about five years I've tried 4831 shortcut could not get the velocity although it was accurate I did have a rather high Es I since have gone to reloader 23 52.5 grains I tried two different primers CCI br2 primer give me an average muzzle velocity of 2947 and SD of 8 and ES of 20. I tried Sellier and bellot primers with an average velocity of 2991 and SD at 3 and an ES of 8 I am also using the 140 grain burger hunting VLD And jamming it .005

 

[Rflshootr]

I'd be running RE-19 with those 140's. Just my opinion.

 

[Clem Bronkoski]

I am running a Berger 140 VLD Hunting, Federal 210M primer, 53.4 H4831SC, .005" from lands, 2960 fps. Again there are no signs of pressure with new brass, hard bolt is fire form brass only. I am thinking about trying 53.3 grains and going to a .015" jump.
Thanks for all the replies and info!!!

So what kind of accuracy are you getting with the new brass that I assume is FL sized? It looks like your problem and the solution is right in front of your nose. Especially if you're not experiencing a big accuracy difference between the new brass and the previously fired brass.

 

[Trnelson]

The reason you don't encounter pressure signs with new brass is that the brass uses some of the pressure to obturate, (expand to conform) the brass to the chamber. New brass is typically a little under size and not perfectly formed. It then springs back a little bit so you can extract it.
On the second firing the brass is closer to YOUR real chamber size, (your chamber could be toward the maximum side of specifications and FL sizing is actually undersizing the brass) and doesn't use that pressure up in obturating and forming the brass. The brass can only spring back so far, regardless of the forming protocols you use and their proximity to your actual chamber dimensions. You are detecting the brass fitting more exactly in the chamber after the second firing. Third firing of the same brass will likely show a even greater indication of excessive pressure.
You are correctly identifying an indication that your load is a bit too stout. H4831sc won't give you the highest velocity, but it is very consistent. There are ways to work on that. Reducing the powder charge primarily, switching to another powder, adjusting the seating depth, changing to a different primer, a combination of the above, ect. IMO, firing only virgin brass isn't one of those solutions I would be comfortable with in the field. I have never had a deer walk away from a 140g bullet, even if it's 100fps slower than I'd like it to be. The rifle makes the rules, your job is to follow them as best as you can. Best of luck with your hunt and new rifle.

 

[scottishkat]

Jeff, I noticed you did not mention where you started the ladder test at. Generally speaking H4831 is a no brainer in the 6.5x284. Usually start around 51 to 53 with a 210M and expect to find 2 nodes 1 higher and 1 lower it is a slower powder for the 6.5x284 but accuracy and ES trump velocity IMO. If you have already tried 51 to 53 another powder is probably in order N160, N165 and H4350 are good choices if available. RL23,26 and Retumbo are also noted for excellent performance.

COAL could change ES I would think a .030 and or .060 off would provide better info though.

Good luck and shoot straight y'all

 

[Jeffrthehunter]

Here is an update that I also added to my original post.

After some thought I realized that the hard bolt issue at 2950 fps seemed new. I have loaded several hundred rounds (ladder testing and fire forming brass) with some loads running over 3000 fps and never had a heavy bolt issue (did have some primers start to crater). I then realized I had changed my brass prep a few weeks ago and started wiping each case below the shoulder with Lyman case lube prior to full length sizing. I would wipe the brass off with a paper towel after sizing but never really cleaned the case. Today as a test I cleaned the rifle chamber and several rounds with de-greaser and went to the range. No heavy bolt lift!!!! So crazy how the small things can cause problems

Thanks for all the thoughtful ideas and info, I will do some more shooting this weekend and give updates if something changes.

Thanks Jeff

 

[Clem Bronkoski]

Jeff for the past, maybe 20 years or so, I've been using Hornady One Shot case lube. I got away from that nasty heavy lube. And no need to clean up afterwards. I just size and put them into my tumbler. Never any buildup.
I'm glad you solved your problem.