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

[Jeffrthehunter]

I have been shooting a new build for a few months (6.5-284 Defiance action with proof barrel) and have really struggled to find a load with low ES. After several attempts I ran a ladder that showed 53.4 to 53.6 of H4831SC was single digits for ES and shoots 1/2 MOA out to 500 yards. Problem is that with fire formed brass I get a hard bolt lift (last 10 degrees), not real hard but there is some pressure there. I know if I drop to 53.2 it will go away but the ES goes to 20 plus. Deer season is just around the corner and I would like to stick with this load (53.4) and maybe try something different in the off season. So the questions is, is this a horrible idea? Will it damage my Defiance action? Any thoughts from you more experienced gentlemen would be appreciated!!!

9/11 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

 

[Rick Richard]

If you are having signs of pressure, I would back down. You never know when you will have a bit of a oops moment and accidentally load a couple of grains more... Then you may be in serious trouble. In the end, the decision is yours.

 

[Mikecr]

Is it a sizing issue?
I refer to a single issue like this as a 'pressure problem' rather than a pressure sign. There is a difference.

Given a 6.5x284 size & form, you will have to size the case body.
If your chamber is soppy, the cases would yield so far as to lose the ability to spring back enough from chamber walls. This, leaving interference fit & popping extraction issues. Not enough barrel steel around the chamber can cause the same. Neither being the result of excess pressure, but they're problems manifesting with increasing pressure.

 

[Trnelson]

I'd say you are topped out and then a bit more. Depending on your barrel length you are either just above 3,000 with a 24" barrel and a 140g or approaching 3,100 with a 26". 53.6g H4831sc is pretty darn stout, I've only had one barrel that could safely shoot that much and it didn't last 1,200 rounds. You'll probably see loosening of the primer pockets within one or two more firings.
Maybe seat the bullet 0.005" deeper and re-test or back off to the next node down. Your primer pockets will last significantly better. Nothing worse than trying to beat a gun open to get ready to take a follow-up shot.
If you have all your data already and don't see something promising lower you can always come back to this load in a pinch.

 

[Jeffrthehunter]

Is it a sizing issue?
I refer to a single issue like this as a 'pressure problem' rather than a pressure sign. There is a difference.

Given a 6.5x284 size & form, you will have to size the case body.
If your chamber is soppy, the cases would yield so far as to lose the ability to spring back enough from chamber walls. This, leaving interference fit & popping extraction issues. Not enough barrel steel around the chamber can cause the same. Neither being the result of excess pressure, but they're problems manifesting with increasing pressure.

There are no pressure signs with new brass. I am using a Redding S die and bumping the shoulder .002, tried bumping shoulder .004 and still had the stiff bolt. I am not seeing any extractor pin mark at 53.4 but I did see some at 53.6. With the weather getting colder pressure will hopefully back off. I only have one or two days to check dope at long distance so changing charge now would suck.

 

[L.Sherm]

Back down the charge and try different primer sometimes different primers will drop your ES.

 

[lancetkenyon]

This is MY opinion, not giving advice.

If I were still shooting very accurately, but have a 20 ES:
If shots will be 600 or under, run the 20 ES load for deer season. I highly doubt i would see enough difference in vertical due to 20 ES that I would notice.

If I were NOT accurate at the lower 20 ES load, but the slight pressure load WAS accurate:
I would run the hot load for deer season, and start load development again after deer season was over. Probably only take one shot during deer season anyway.

I would try changing primers (you didn't state what primers you are using), changing seating depth, changing neck tension, or even powder.
I would NOT bump shoulders back further to .004".

Have you checked with once fired brass?

 

[Mikecr]

Yeah excess bumping of shoulders will do nothing 'good', ever.

 

[Hespco]

You are over pressure. Please back down now before you have a catastrophic failure. Your load is Max +.

 

[jimwest]

I have been shooting a new build for a few months (6.5-284 Defiance action with proof barrel) and have really struggled to find a load with low ES. After several attempts I ran a ladder that showed 53.4 to 53.6 of H4831SC was single digits for ES and shoots 1/2 MOA out to 500 yards. Problem is that with fire formed brass I get a hard bolt lift (last 10 degrees), not real hard but there is some pressure there. I know if I drop to 53.2 it will go away but the ES goes to 20 plus. Deer season is just around the corner and I would like to stick with this load (53.4) and maybe try something different in the off season. So the questions is, is this a horrible idea? Will it damage my Defiance action? Any thoughts from you more experienced gentlemen would be appreciated!!!

Thanks Jeff

I looked over all the replies and didn't see where you mentioned what bullet you are loading? Is it a 140 grain? Berger, Barnes, Hornady, Nosler

 

[Jeffrthehunter]

I looked over all the replies and didn't see where you mentioned what bullet you are loading? Is it a 140 grain? Berger, Barnes, Hornady, Nosler

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!!!

 

[7mmTikkaShooter]

I don't shoot the 6.5-284 so I'm unfamiliar with the load data. Out of curiosity I went to Hodgdons online reloading data and discovered that with 4831 there are only 3 bullets listed where over 53 gr wouldn't be over max, and those bullets are on the light end target or varmint type. Gotta ask what bullet you're shooting and is it suitable for hunting deer? From what I'm seeing with virtually every bullet 120 gr or heavier your load of 53.6 is substantially over charged and probably dangerous. If it's one of the lighter bullets then I'd still drop to the lower charge since those lighter bullets are not really something I'd shoot a deer with, especially past 500. The e.s. of 20 won't likely be an issue.

 

[jimwest]

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?

 

[L.Sherm]

Lance is correct on the ES, Only makes .5" difference to 500 with a 20 FPS spread.