Hitting pressure after a bit of load development

[coast range]

So I already know I am hitting pressure but it was surprising to me in how it started.
6.5 prc and ran 100 rounds messing with powder charge and never hit pressure but settled on 59gr on 565. I went to 60 initially. I had 100 adg that I did one firing on then loaded 10 for a second round to check for pressure…all good.

So I head to my cabin(5200’) in eastern Oregon as I live on the coast where I did load development. First evening I run about 15 rounds before dark all good. Next day, it pretty chilly for this time of year there maybe mid 50’s about the same as here on the coast.

About 8 or so rounds in I start to get a stiff bolt lift, I have never gotten one on this rifle, and get a slight ejector mark. Dang.

I stop shooting and come back next day and same thing. 8 or so rounds and all of a sudden I’m hitting pressure.

So have you guys seen this before? And now how do I begin loading again? Drop a couple grains? Thanks and sorry for the ramble thought I was gtg….

 

[SDHNTR]

Yep. Drop at least a grain.

 

[ResearchinStuff]

I've had loads that were good suddenly start showing pressure due to case lube build up in the chamber. If you're not being meticulous about getting the lube off check that first.

Also, if you have a bore scope take a peek for a carbon ring, if you don't have one by the teslong, then take a peek

How much did you bump the shoulder, and how far are you from the lands? Inadvertently jamming will spike pressure too.

If none of that fixes it, drop your powder charge.

 

[coast range]

I don’t have a scope, there is now about 125 rounds down the tube.

I did only use a dry rag to clean off case lube, that’s All I have ever done but interesting idea.

I’d have to look at my notebook but I should be plenty far from the lands, and I bumped shoulders right about .002” I used Eric cortina’s method of bumping til the bolt handle just falls down. Thanks for the ideas

 

[mtnbound]

So I already know I am hitting pressure but it was surprising to me in how it started.
6.5 prc and ran 100 rounds messing with powder charge and never hit pressure but settled on 59gr on 565. I went to 60 initially. I had 100 adg that I did one firing on then loaded 10 for a second round to check for pressure…all good.

So I head to my cabin(5200’) in eastern Oregon as I live on the coast where I did load development. First evening I run about 15 rounds before dark all good. Next day, it pretty chilly for this time of year there maybe mid 50’s about the same as here on the coast.

About 8 or so rounds in I start to get a stiff bolt lift, I have never gotten one on this rifle, and get a slight ejector mark. Dang.

I stop shooting and come back next day and same thing. 8 or so rounds and all of a sudden I’m hitting pressure.

So have you guys seen this before? And now how do I begin loading again? Drop a couple grains? Thanks and sorry for the ramble thought I was gtg….

Confirming you are not seeing pressure signs until 8 or so rounds are fired. No sign of pressure in the first few rounds fired?

 

[coast range]

No obvious signs. Primers seem fine, no heavy bolt lift and no real ejector mark

 

[Jason Snyder]

How many loadings on the cases? Are these sized once? Twice?

 

[coast range]

Sized once adg brass. Tikka rifle.
59 gr 565
Gm 210
Eldm 147

 

[Jason Snyder]

I never do a pressure ladder on new brass. I use oncee fired twice fired to find pressure.

 

[Montucky]

I had this same exact experience with ADG Brass on my 7saum. Found a load shot well no pressure. Was at 64.0 H1000. But after second firing on brass I started getting pressure signs. Almost like brass quits expanding & there’s no more room for expansion. Found 62.0 H1000 shot just as good & no pressure on 3rd firing

 

[Hudsflywater]

I would look for a carbon ring as "researchingstuff" mentioned. one way to check for one is to load a fully loaded round into the chamber, make sure the bullet is smooth with no marks, then unload that round, if there are scratches on the bullet, its engraving into carbon. Although the best way is to get a Teslong, there'r pretty cheap and work great..

 

[Koda_]

I don’t have a scope, there is now about 125 rounds down the tube.

Have you tried cleaning the bore?

Just in case, if this is a new rifle the velocity and pressure will increase some after the barrel fully develops its firecracking, generally between 100 and 150 rds to fully "break in" a barrel. A dirty bore adds to the issue.

 

[coast range]

Sitting at about 125 to 135 loads. I was going to clean the rifle at 200, the end of my week at the cabin. But I stopped shooting this rifle because of the pressure.

 

[Koda_]

Sitting at about 125 to 135 loads. I was going to clean the rifle at 200, the end of my week at the cabin. But I stopped shooting this rifle because of the pressure.

So your right about or at your firecracking break in limit. Clean your bore thoroughly and your pressure will go down but this also might indicate your handload is near or at max pressure. Keep your bore clean to shoot higher pressure handloads or back off a couple grains and drop some velocity.

heres a Bryan Litz video explaining this firecracking and barrel cleaning influence on pressure.

 

[Harvey_NW]

59gr N565 is SPICY in a Tikka and PRC case. Pressure increases with formed brass, drop your charge and it will be fine. I loaded 58gr on new brass and dropped to 56.5 to get completely clear and safe on formed ADG in mine. The cleaning argument always makes me laugh, because you'll end up shooting 20 rounds to get the groups and velocity to stabilize again anyway, I wouldn't touch it.

 

[coast range]

59gr N565 is SPICY in a Tikka and PRC case. Pressure increases with formed brass, drop your charge and it will be fine. I loaded 58gr on new brass and dropped to 56.5 to get completely clear and safe on formed ADG in mine. The cleaning argument always makes me laugh, because you'll end up shooting 20 rounds to get the groups and velocity to stabilize again anyway, I wouldn't touch it.

Ok sounds good. I will pull what I have and drop the charge.
What barrel length are you using? Mine is 20”. I was only getting 2770 with the 59gr. I knew before I chopped it would be slow but not that slow!

 

[Harvey_NW]

Ok sounds good. I will pull what I have and drop the charge.
What barrel length are you using? Mine is 20”. I was only getting 2770 with the 59gr. I knew before I chopped it would be slow but not that slow!

It's 21-1/2" from the shoulder, factory Tikka barrel cut back to the end of the flutes. I'm at about 2850-2900 with 56.5gr depending on temp. Yours might speed up a bit after you get 2-300 rounds on it too, but sometimes Tikka barrels are just a bit slow, their only downfall.

 

[wind gypsy]

Chamber and throat cleaning at least to make sure there isn't any lube in there seems to help.

Un-rokslider of me but some of the slow barrels and sticky bolt lift that tikka's seem more prone to is starting to sour me a bit on them now that they make up most of my bolt rifles..

 

[HandgunHTR]

Chamber and throat cleaning at least to make sure there isn't any lube in there seems to help.

Un-rokslider of me but some of the slow barrels and sticky bolt lift that tikka's seem more prone to is starting to sour me a bit on them now that they make up most of my bolt rifles..

Here is my take on it. I will gladly give up 75-100 fps for a barrel that shoots everything well rather than a "fast" barrel that is super sensitive to seating depth or only likes one load. But, then again, I have never been one to chase velocity. I can always dial up another click.

 

[Harvey_NW]

Here is my take on it. I will gladly give up 75-100 fps for a barrel that shoots everything well rather than a "fast" barrel that is super sensitive to seating depth or only likes one load. But, then again, I have never been one to chase velocity. I can always dial up another click.

I honestly don't think it's as bad as people make it out to be and it's just overblown expectations, and bad internet data. And if it is, it's usually 100fps at most from the realistic top end which is negligible, like you said.