help with pressure signs, loads below book minimum

[el matador]

Re: AR2217 Is H1000

You're still 10-12 grains below the published max data, which is an enormous amount. I would check your powder. Maybe you used H4831 instead of H1000? Maybe you got a bad lot of powder? If possible, try some loads with a new bottle of powder from a different lot. Or try a different powder altogether. If you get the same results at least you've eliminated the powder as the culprit.

79.0 grains is about the max load for a 300 SMK with H4831. If your powder got switched somehow I would expect the exact results you're describing for pressure and velocity.

 

[climb-101]

Re: AR2217 Is H1000

i don't think it's the powder. i have tried i have 3 different lbs from 3 different lots. plus i use it in my 7stw and i have no issues with that rifle, it's just a factory remington i use for hunting

 

[Beneviolence]

I am currently having similar issues; pressure signs at relatively low loads. It looks like you already checked the distance off the lands so you know you're not jamming them on there while thinking you're lowering pressure by seating it out further...which is what I did at the start. My brass grew 0.010" on the first firing, showed flattened primers at all loads (min and up). I believe I have excessive headspace, so it is currently at Savage right now.

Thread link: http://www.longrangehunting.com/forums/f28/338lm-pressure-signs-180687/

 

[dok7mm]

Climb-101, I just plumb forgot to mention in my first post, that I did have a similar problem with two Stiller actions. One was a 6.5-284 on a Predator and the other was a 7mag on a Tac 300. Both exhibited ejector marks on brass with starting loads. I sent the 6.5 bolt back to Russ @Stiller and got it back shortly, with a repolished ejector. On the 7 mag, my Smith also polished the ejector. Both had very slight high spots where I was seeing brass. After polishing, no problem with pressure signs until I was at max velocity. May not be your problem, but I would examine the ejector under magnification. Did you ever notice harder bolt lift, or was it just ejector marks and primer appearance? Sometimes, it is the simple things.

 

[climb-101]

Climb-101, I just plumb forgot to mention in my first post, that I did have a similar problem with two Stiller actions. One was a 6.5-284 on a Predator and the other was a 7mag on a Tac 300. Both exhibited ejector marks on brass with starting loads. I sent the 6.5 bolt back to Russ @Stiller and got it back shortly, with a repolished ejector. On the 7 mag, my Smith also polished the ejector. Both had very slight high spots where I was seeing brass. After polishing, no problem with pressure signs until I was at max velocity. May not be your problem, but I would examine the ejector under magnification. Did you ever notice harder bolt lift, or was it just ejector marks and primer appearance? Sometimes, it is the simple things.

the ejector mark/primer is all i'm going off. i will take a look at the ejector with a magnifying glass and see if i can find any burrs. if there is one that would make sense as to why it's leaving marks. if there isn't one, guess i will just back it down a little and and if everything looks good i will run it. on the plus side i will save a little power

 

[climb-101]

i did some more looking around and trying to figure out why i'm getting pressure signs. I watched a video of how to find the when the bullet touches the lands. in the video the guy strips the bolt (firing pin and ejector). he then seats a bullet long and keeps seating it deeper and tests it in the gun. the bolt holds the casing and as you shut it you can feel it hit the lands. I also marked the bullet with a marker and could see the lands touching. i kept seething he bullet in by .001 until there was no marks on the bullet. i then used the previous length to determine my length. I have a big differance between the horniday setup and doing it this way, roughly .150". i'm wondering if the bullet wasn't being jammed causing my pressure. my loads seem on the short side now @ 2.869" base - ogive which is a .010" jump.

i'm wondering if the barrel was either chambered short if that is shuck a thing or if it was setup for a different type if bullet like a berger instead of the 300 smk like i am running. any thoughts on this? thanks

 

[dok7mm]

Congrats! I use basically the same method, but I seat deeper until bolt drops freely.This shows accurately when bullet is free of lands. Using fired case, this will also help you find exactly how much to bump shoulders back. I haven't used the Hornady oal gauge in a long time. I do use the comparators for measurements.

 

[TonyQ]

I figured that was the problem. I was having the same problems with my hornady tool also. The hornady comparator was contacting the ogive at .325 when the lands is at .338. I tried calling Bob Green to see if he would make me one but he doesn't make one for the .338. Here is the one I am looking at buying I just need to call them to see what there inside measures at. New Page 1

 

[climb-101]

i went out just to try a few rounds, i shot one at each of the following 78, 79, 80, 81 grains of h1000 they were loaded to 2.869" base to ogive. the primers are still flat like before but there isn't the ridge around the firing pin strike like there was before when it was at the longer load length even at the same power charge. it's still leaving a slight ejector mark even down at the 78 grains of power. i might try dropping it down to 75 grains and seeing if that gets rid of the ejector mark. i thought by seating it deeper would have solved my issues cause it was jamming the bullet but it didn't, it looks like it helped a little though.

 

[gohring3006]

When you loaded up more rounds, did you use the once fired brass or new?

 

[climb-101]

once fired brace is what i used.