very hot 6.5-284 question

[bow shot]

I see in IMR's load data that the charge range for the 142 gn bullet for H4350 is about 42-46 gn.

I also see that in the 6.5-284 mainpage side-bar article (here on this site) that some of the folks are loading up to 49gn.

...so... I was shooting a 500y ladder, and found my bolt beginning to get difficult to raise as soon as I breeched the 48.6 gn. point. Unfortunately, I hit a fantastic load area in the 48.8-50.2gn area (0.75" vert 1.5" horizontal), but the bot lift at the hottest load got... scary. I really didn't like the amount of effort it took to cam open in that range, sorry I can't quantify.

The questions are:
1) Are the hot load shooters shooting actions/barrels that do not exhibit this behaviour?
2) should I trash the brass that corresponds to the difficult bolt lift?

BTW...Wislon case gague should be on my porch today.

Savage 111 med contour 26" w/ factory brake
Normal COAL (whatever IMR's site said.. I fergit)
Sierra 142 Matchkings CCI BR4's
Laupua 2x fired (F/L sized) brass

 

[308sako]

I'm no expert, and only on my second 6.5/284 barrel now. The first was a HART tube and this one is a Rock that has been QPQ'd or melonited by Joel Kendrick's people. The newer barrel has been giving me issues with pressure at charges far below what the older barrel allowed. Just goes to prove that each rifle is an individual unto itself. Since I have on hand slower powders than the H4350 those are what I choose to use. Specifically H 4831 SC. My current maximum is 50.0 grains for a velocity of 2950 ft/secs. Fortunately the rifle shoots this load very well, 400 yard testing at less than .3 MOA.

One of the interesting phenomenons I have noticed is that longer barrels give apparently higher pressures... although this isn't the actual case! Rather it is the dwell time that the pressures have to work on your brass or primers that create the illusion of higher pressures. It was the use of a suppressor that taught me about this aspect of reading the indicators.

Sorry I'm getting away from your intended query; sounds like you do have too high a pressure load for your barrel. By carefully fitting your cases to your chamber, and playing a bit with seating depth, you should be able to mitigate to some extent the signs you are getting. If not, switch powders and begin again.

 

[jo191145]

No expert either. As a short range shooter I have toyed with three different 6.5X284 barrels on Savage actions just for fun.

On the 6.5x284 page (somewhere) I noticed one shooter state that these velocities attained are actually not stout loadings for the 6.5.
Although book data is still much lower and slower.
That's what I've found also. Never had any pressure problems pushing past the loads listed on this site much less book data.

Does'nt explain why your having issues but thought it might be beneficial to know my Sav's can do it with ease.


Throat fouling is a big problem with the 6.5 if your cleaning regimen is not good enough. Sav barrels can be quite fussy about fouling and of course that can lead to over pressure signs wher normally there would be none.
If one lug is not making good contact on a Sav action I could envision that allowing the case to grow too much causing difficult extraction. Shot a lot of Sav's and never seen that problem, the floating bolt head is supposed to help eliminate it but,,,,,,,,


You mentioned IMR data yet your using H-4350???? Is something wrong with that info?

 

[bow shot]

"You mentioned IMR data yet your using H-4350? Is something wrong with that info?"

I am actually using IMR, not H..., but I see that on the Hodgdon Burn rate chart they are neck and neck, with H being a tad faster.

Well, sounds confusing, I know, but the IMR web page does give the H powders too. Kinda strange that they don't even give IMR 4350 data for the 142 gn bullets??

Using the wilson case gauge now, results to follow!..

 

[markr]

I see in IMR's load data that the charge range for the 142 gn bullet for H4350 is about 42-46 gn.

I also see that in the 6.5-284 mainpage side-bar article (here on this site) that some of the folks are loading up to 49gn.

...so... I was shooting a 500y ladder, and found my bolt beginning to get difficult to raise as soon as I breeched the 48.6 gn. point. Unfortunately, I hit a fantastic load area in the 48.8-50.2gn area (0.75" vert 1.5" horizontal), but the bot lift at the hottest load got... scary. I really didn't like the amount of effort it took to cam open in that range, sorry I can't quantify.

The questions are:
1) Are the hot load shooters shooting actions/barrels that do not exhibit this behaviour?
2) should I trash the brass that corresponds to the difficult bolt lift?

BTW...Wislon case gague should be on my porch today.

Savage 111 med contour 26" w/ factory brake
Normal COAL (whatever IMR's site said.. I fergit)
Sierra 142 Matchkings CCI BR4's
Laupua 2x fired (F/L sized) brass

A little common sense could go a long way to save your face..........no, really!

 

[bow shot]

Ok, so I popped the primers out of the coolest and hottest (spent) rounds, and I see that all cases fit the Wilson gauge properly. The hot cases were darn close for length at the neck, but squarely within the limits at the head.

I was expecting that the difficult to extract ones would be long in the gauge at the head-end

Returning the cases to the rifle, the cool cases chamber as if they were unfired, and the hot cases, though the fit the wilson gauge well, chambered tight.

Comments (other than, "don't blow your head off, lol!)?

 

[XTR]

Based on what I've done, some of which amounts to destructive testing of 308 brass for F-TR the answer will be in your primer pockets. Hand seat them and see how they feel.

When I get to the point you are describing with a 308 I either get one more load or none at all. Last month I trashed 60 Lapua small pocket Palma brass in one shot.

 

[bow shot]

yeah... I'm not expecting good things, lol! Just tumbled and re-sized, and didi the remaining brass prep. Some needed just a tad of length trimming, but I couldn't see any association on the case length vs the hot-ness (ei, some cool loads needed trim, few hot loads did need trim).

Primer seating next!!

 

[308sako]

OP, a bullet does enter your fired brass freely?

On the case gauge, the chamber is a far better item to use as that is where you are exerting pressures. I measure everything I can think about regarding my brass, first 10 virgin cases, then 10 loaded cases, then 10 fired cases and lastly the 10 cases re-sized to fit my chamber with a minimum of head space setback. Then I look to see where my averages fall, and see what direction the brass is moving in.

For my experience this cartridge is one that operates best at higher pressures and velocities.

Once again good luck.

 

[lightman]

I'm shooting hotter loads than that, with no problems. So, every rifle/barrel is different. My favorite powders are 4831sc and rl-22. I'm clocking in the 3030-3040 fps range, and cases last 12 or more firings. A hundred cases will wear out my barrel! That is with a 142SMK. Listen to your rifle, please don't go by others data. There are lots of different chambers in 6.5-284, so please be cautious. Lightman

 

[bow shot]

YEs.. treading lightly now!

Hmmm... I'll check the bullet-into-fired brass thing tonight.

I see also that my sizing die is pushing the shoulder back 0.005". Maybe a tad too much? I'm using a Hornady sizer with the neck honed, with a few Skip's shims added to decrease the original bump.

 

[bow shot]

Also... sinced the fired cases fit the Wilson gaguge so well.. I wonder if the difficult extraction was from bulged cases? Ie., the Wislon gauge is all about length, not diameter...

No more cases left (that extraced hard) that I haven't sized... so I can't check diameter now..

 

[jo191145]

YEs.. treading lightly now!

Hmmm... I'll check the bullet-into-fired brass thing tonight.

I see also that my sizing die is pushing the shoulder back 0.005". Maybe a tad too much? I'm using a Hornady sizer with the neck honed, with a few Skip's shims added to decrease the original bump.

Definitely more than a tad too much. If you've been bumping the shoulders back that far or more before the shims you may have weakened the brass enough in the web area to cause hard extraction issues. Case web failure comes next.

.005" + the normal .002" springback on virgin brass = .007" headspace on every firing. Too much.

A FL die should be set high making it essentially a neck sizer until you get some hard to chamber brass. Then by measurements you can adjust your FL to begin doing its job. Otherwise its just more hope and change.

 

[bow shot]

Yes, I'm now thinking that my troubles began when I installed my Horandy sizer by RCBS's instructions:

• RCBS says bring the ram up all the way, and then screw the die down until it touches the shell holder.
• Hornady's says to bring the ram up but NOT to let it cam over, and then screw in the die until it touches the shell holder.

I then shimmed the die up from there until I had no resistance to closing the bolt on a sized case.

'should have started with a gauge instead of the "feel" method.

Anyway, whatever it all comes to... it didn't work.

I measured that one and only fired but un-sized case that I had: only .001" below maximum length (on the Wilson gauge).

So the question now is: Should I discard this brass?

 

[bow shot]

Correction: I'm bumping 0.003"- 0.004". Just sat down and did a lot of measuring with the Wilson gauge and a good caliper. I get the same #'s using a Starrett Depth mic.

 

[bow shot]

Just wanted to update folks on this in case anyone is wondering, "I wonder whatever became of that bloke?"

Well, I took Boyd's advice, and set the Wilson case length gauge aside, and went with a Hornady comparitor set up. The wlson gauge just wasn't a good "rep" of my chamber.

I'll be starting from scratch: fire, measure, fire, measure, and then set the shoulder back accordingly.

Unfortunately, have to wait till spring...

I tossed the brass that generated the difficult bolt lift.

 

[Bob Sebold]

I don't know what you are shooting with that hot a load, hunting or completion. I can tell you when I used to shoot it 51 grs of 4831 SC hammered pretty well. But, did it burn barrels fast. 800 to 900 rds and that barrel would go beyond 1/2 minute accuracy. I switched to straight 284 and barrels last a lot longer.

 

[wyoming .260]

The whole idea that your cases are wasted in one loading seems to tell me you need to forget that load and start over. All guns being different and acting different, I would Try a different powder something a little slower, H1000 has shot real well out of a 3 different 6.5-284s I have seen and shot,..

Just my opinion,its your eyes and face,Be safe.

 

[bow shot]

Shooting for bullseyes, I only compete against myself, i.e.., tighter and tighter groups... I don't think I could actually compete with anyone that is a reasonably good marksman.

And yup, I aint gonna blow a piece of myself off over this. The doubtful brass has been trashed, and I'll be starting fresh.

I might get a bit of shooting in over the winter, but I don't go nuts over is since my "real" shooting will be happening in the 50 - 80 degree range, not the 10 - 30 degree range we have here (liberal nut-job infested central NY) now. Mainly just some brass prep and whacking squirrels with the bow or the .22...

 

[Webster]

It sounds like you want to discard all signs of high pressure and you are determined to shoot high powder charges that other people throw out on internet. Back off until bolt lift and other signs of pressure go away. It's not worth having an action blow up in your face. You should be wearing safety glasses when shooting. If you need more velocity try different powders. It isn't just damaging brass you could be killed or blinded if a rifle blows up in your face. Have you tried RE-17 for more velocity at safe pressure.

You tried 49.0-50.2 grains?

The Sierra manual for the 142 gr Match King states 44.5 grs of 4350 max charge
The Berger manual 140 gr bullet 46.8 grs of 4350 max charge.