pressure signs at min load?

[B.W.]

So I have a howa 1500 chambered in 25 06 that will show light ejector marks even at min starting load? The higher I go the worse the marks get and heavy bolt lift soon follows. I have not been able to get half way through a load work up with the three different powders I've tried(imr 4831,h4831sc and re22). I neck size (lee collet) with brass fired from this gun and im seating well off the lands. Has anybody else experienced this? What would cause a gun to have pressure issues like this. Any insight would be greatly appreciated.

 

[morcey2]

First thing I would do is double-check and triple-check your scale and charge weight. Are you using a different manufacturer's case, primer, or basic bullet shape/construction than the reloading manual?

Matt

 

[B.W.]

Im using a digital scale but I also have beam scale I check with periodically. I load for other rifles and do not have this problem. Right now I'm using berger 115 gr vlds, cci# 200 lr primers, norma brass. I have used many different combos of bullets, primers and powders for this gun with the same kind of outcome. I have the berger manuel plus 4 others.
I

 

[243winxb]

Light neck tension, slow powder, long OAI with little bullet shank in case neck may produce a secondary pressure spike when the bullet moves to soon.. Others- undersize groove diameter in the barrel. Using bullets of a different construction then in the published reloading data.

 

[Andrew Leigh]

The most common reason IMO for signs of pressure on light loads is excessive headspace. Were your primers by any chance a little proud of the case post firing?

Please post your load (powder and charge weight), bullet and COL along with the brass head stamp and lets run your load through QL to see how "light" it is.

 

[B.W.]

Yeah the primers are slightly proud. Could it be head space problem even though I'm neck sizing with brass that has multiple firings?

 

[Andrew Leigh]

Could be a host of things;

When last did you trim your cases to length.
When last did you anneal?
When last did you bump your shoulder back with a FL die?

Please quickly post your load data, lets eliminate what we known first.

 

[B.W.]

Brass are all trimmed to 2.484. I've just recently got started annealing but haven't annealed these brass yet, the brass I have are on there 2nd and 3nd firing. I don't normally bump the shoulder back until they get little stiff when chambering. For that process I have a redding body die and bump back .002.

Berger 115gr vld
CCI 200 lr primers
Reloader 22
Neck sized norma brass
2.690 base to ogive

My starting load was 49.5 gr

 

[Andrew Leigh]

I know base to ogive is best is best but in this case I need base to tip please, will start the calcs.

 

[B.W.]

Thanks for your help

3.280

 

[Andrew Leigh]

You are running at 39 200psi which indeed is very light.

Even into the lands you would typically add 7 500psi so you would still be fine.

Possibly not head spacing as you speak of hard bolt opening at times. Can only think that the neck is hard against the chamber allowing no blowback. A ring of heavy burnt carbon around the neck is diagnostic of light loads as there is insufficient pressure to seal the neck against the chamber. If you have no heavy carbon deposits then the case may be too long and sealing at the front of the chamber.

 

[OYE]

Is this a new rifle? A recently acquired used rifle ? Or a rifle you have owned for a long time that is just now having problems ?

Have you shot any factory ammo in it ? If so what does that brass look like ?

I think about any local gunshop to you should have that headspace gauge if they do any work at all. It's easy enough to have it checked.

While I'm thinking about it. At what point in the increase in powder charge (Reloader 22) are you getting the sticky bolt ? Any other pressure signs like flattened primers ?

Have you tried any other brand of brass with the same results ?

The brass you are using was purchased by you and you know it's only been fired 2 to 3 times.

And you are absolutely sure your scale is measuring correctly.

OYE

 

[B.W.]

Once again thanks for the help Andrew.
I bought the rifle new a few years ago. I did fire some factory rounds when I first bought it. I don't recall having any pressure issues with them but I doubt I really looked. It's a hunting rifle so when I first starting load development after buying it I just settled for a light load with the powder I had and never really messed with it again until lately. Maybe ill take it to my gunsmith and see what he can tell me

 

[B.W.]

The brass I have was brand new and I had different brass before this norma brass. The powder charge is the first thing I thought of as well. I have check weights and two scales, digital and beam. I do quite a bit of shooting and reloading and like I said I load for other rifles with same equipment with no issues

 

[Andrew Leigh]

Barrel squeaky clean?

 

[BigBore45]

"secondary" detonation or w/e they call it? Maybe try a magnum primer. i do not think it is head space if he ran factory rounds through it without seeing anything weird. and out of curiosity what did those loads crony at??

 

[OYE]

I suspect the chamber may be a little rough. It may need additional polishing.
Assuming the headspace is o.k., since it is a relatively new gun and a one-owner, it should be. What you are experiencing is not unheard of and isn't that uncommon on certain brands of rifles in years past, but not Howa.

You might choose a local gunsmith that can inspect the chamber and then go from there. Or continue with the light loads as you have been doing. OYE

 

[B.W.]

To finish answering your question OYE, the sticky bolt started at 52.5 gr. The Berger Manuel states 49.5 min - 55.2 max.
Yeah the barrel is clean

 

[B.W.]

One thing I still don't have is cronograph. So couldn't tell you velocity

 

[OYE]

Expected you to say mid-range or slightly past when working up a load (seen that a few times before). Would be consistent with a chamber that's a little bit rough. Rifles like that can still be exceptionally accurate even with the lighter load. Think you've got all the other bases covered though. OYE

 

[Andrew Leigh]

No one, for all my reading on the matter, has ever been able to load to create secondary detonation. And I have searched, it would appear to be a theoretical rather than practical consideration. Besides the case fill is 92%, secondary detonation is derived from a very low case fill.

 

[Andrew Leigh]

To finish answering your question OYE, the sticky bolt started at 52.5 gr. The Berger Manuel states 49.5 min - 55.2 max.
Yeah the barrel is clean

Even at the load you should be more than OK.

Could you measure the H20 case capacity of the fire formed cases for me? Average out 5 readings. Use a little soap to cut the meniscus and fill to level with the top of the case.

Weigh case dry record, fill and weigh case wet. Subtract the one from the other for the H2O grains.

 

[Andrew Leigh]

Something for you to muse on.

The rule of thumb is slow burning for heavy bullets and fast burning for light bullets. APART from your pressure problems you may want to consider a slightly faster burning powder once you have found problem.

Some theoretical near max loads - DO NOT LOAD FOR ILLUSTRATON
RL 22, gives a burn rate of 0.3860 and with 100% case fill will give 3 151fps, pressure OK. Barrel time 1.153ms.
RL 19, gives a burn rate of 0.4500 and with 98% case fill will give 3 200fps, slightly overpressure. Barrel time 1.098ms.

Most people rate H4831SC as the powder for 25-06, it has a burn rate of 0.4301, somewhere between the RL22 and the RL 19

H4831SC, gives a burn rate of 0.4301 and with 100% case fill will give 3 144fps, pressure OK. Barrel time 1.115ms.

So you can achieve the same speed but with different barrel times allowing you to reach faster accuracy nodes as the powder burns quicker.

 

[243winxb]

25-06 RL22 Berger 115gr

the sticky bolt started at 52.5 gr. The Berger Manuel states 49.5 min - 55.2 max.

Note that Allliant data maximum is 52 gr with a different bullet. Steve's pages list RL-22 From 48.5 grains to 52.5 grains. http://stevespages.com/page8a.htm
http://www.alliantpowder.com/reloaders/powderlist.aspx?type=1&powderid=14&cartridge=55 Berger VLD may come in 2 different jacket thickness? Just checked, only 1 bullet availabe) Thicker jacket makes more pressure. Hard bolt lift tells me you have found the maximum loading. Now back off the powder charge till you find acceptable accuracy.

 

[notaglockfanboy]

BW, I have a Howa 1500 in .308 and am dealing with the same issues. It happens with factory ammo and reloads. I got some brand new Lapua brass and started working up my loads, and even the minimum loads give me the ejector half moon. From minimum to just below max I am seeing this. What puzzled me is the mark don't get any more pronounced, there are no flattened primers, and bolt lift is fine. Those loads are seated at 2.800 using 41.0g to 44.0g RL15. I would have been concerned, but it happens with every round fired from the rifle, with that being said if you start getting a mark where the ejector hole is scraping brass from the case, back off your charge as they are a little hot.