Help a n00b with reading pressure signs

[callen3615]

Hey guys, ive been gradually increasing my loads in the last few months and Id like to know if im approaching too much pressure on some of this brass.

Rifle:

308 rem 700 sps varmint 26"

Loads:

178 amax
43.5gr 4064 IMR
2.81 OAL
Win primers
Federal brass



9 of those are the 178 load, the one piece of PMC on the end is from a different, lighter load (168smk 42.4gr 4064). you can see that the primer is more rounded on the sides than the hotter 43.5, 178 loads.

Are these flat primers? Should I back down? I have no chrono but after zeroing today at 100 I needed around 12 MOA to get out to 500. I was shooting steel so I dont know exactly where it impacted though.

Thanks

 

[wilecoyote]

Re: Help a n00b with reading pressure signs

Sir, when I see on my primers the same little,higher ring I see around the firing pin mark on yours, I call it a craterizer primer sign, and it sound me as the rattlesnake tail sound _ I play with a 700 lhvs but,even if generally can be other causes to produce those craterized primers,for sure I will think first to lighten my reloads_ ...only my 2c._

 

[callen3615]

Re: Help a n00b with reading pressure signs

You think these are dangerous? or just nearing max? Id hate to pull 50 rounds tonite.

 

[lovetsx]

Re: Help a n00b with reading pressure signs

Looks just like mine... Been shooting my load for years without a problem.
What type of primer? WLR is much softer than CCI. that flow is because of the gap between firing pin and bolt. I look more at the edge of the primer next to the side of the primer pocket. does the primer still have a rounded radius or is it square. How does your bolt lift feel? That is what tells me that I am at max.

Far right one is max. also notice extractor swipe
Some one on the hide posted this

 

[callen3615]

Re: Help a n00b with reading pressure signs

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: lovetsx</div><div class="ubbcode-body">Looks just like mine...
What type of primer? WLR is much softer than CCI. that flow is because of the gap between firing pin and bolt. I look more at the edge of the primer next to the side of the primer pocket. does the primer still have a rounded radius or is it square. How does your bolt lift feel? That is what tells me that I am at max.

Far right one is max. also notice extractor swipe
Some one on the hide posted this

</div></div>
Yes they are winchester.
Not sure how to judge whether the edge of the primer is square or round, thats pretty releative.

My bolt lift was easy, not sticky at all. And ive never seen the extractor swipe on any of my cases.

I think im ok.


Thanks

 

[FLIGHT762]

Re: Help a n00b with reading pressure signs

I'd say you're getting up there. Looking through my loading manuals, Hornady lists max with 4064 and the 178 A Max at just under 42 grains. Sierra lists 42.8 grains of 4064 max with their 175 OTM. Hodgdon does list a max with 4064 with a Sierra 175 OTM as 45.6 Grains. That does look to be a bit higher than the other two sources.

You are using Federal brass, which are thicker cases with less internal volume than some other brands. The other thing to consider is if this load was tested in 50º temps, you may get more pressure with increase in temperature. IMR 4064 is not as temperature insensitive as some newer powders.

I recently had an issue with IMR 3031. I loaded 43.0 grains in my 308 Win. (a max load) with a 155 Nosler OTM. No issues when the load was tested at and shot at 60º. When I used them a couple of weeks ago in 95º temps, I loosened the primer pockets of my brass and had to toss them.

I don't think you're at a point of disassembling them. You can check to see if your primer pockets were stretched, that's a good sign of over pressure. I'd just be aware of the temperature since higher temps may cause pressure spikes. You just have to understand about that and adjust your loads accordingly.

There are newer powders on the market that are less temperature sensitive.

I have been burning up my IMR powders and I have switched to some of the Hodgdon extreme line powders.

There are threads here that discuss powders that are better suited in temperature extremes.

 

[callen3615]

Re: Help a n00b with reading pressure signs

Maybe I shoot wait til the winter to shoot the rest of my 44gr 178 amax loads.

I only bought 100 of them, just ordered 500 175 smks so that will be my main focus.

 

[turbo54]

Re: Help a n00b with reading pressure signs

Those are G2G. FC brass is soft and will start to "push a button" sooner than most. You'll know a FLAT primer when you see one. You'll say "whoa! Thats FLAT!". Besides that, you should be looking for a circular mark on the casehead like the one pictured below:

This is a heavy duty, classic sign of "pushing a button". The brass has literally flown into the ejector hole in the boltface. Note this one came out of a Savage, which has a smaller diameter ejector hole than a Remington, so a Remmy's button will be a little larger in diameter.

The case on the bottom right has a much fainter one at 7 o'clock. The case on the bottom left has a fainter one yet, also at 7 o'clock.

NO ejector mark like these is acceptable.

 

[turbo54]

Re: Help a n00b with reading pressure signs

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cpt. obvious</div><div class="ubbcode-body">Maybe I shoot wait til the winter to shoot the rest of my 44gr 178 amax loads.

I only bought 100 of them, just ordered 500 175 smks so that will be my main focus. </div></div>

In the 175ish class, the Hornady 178hpbt "match" is the hands down winner. You can drive them faster than the others, PLUS they're BC is appreciably higher. .53 vs .495 PLUS they're cheaper! One of those rare win-win-win situations.

 

[callen3615]

Re: Help a n00b with reading pressure signs

thanks buddy

 

[rusty815]

Re: Help a n00b with reading pressure signs

Hmm, I don't take primer cratering and flat primers as signs of pressure. My 300WSM will start to get relatively flat primers with mild charges for some reason, so I mostly disregard that unless its REALLY flat, the one sign I look for is sticky bolt lift, since that usually comes a grain or two before a blown primer from my experience. If there's no sticky bolt lift, then I think my load is safe.

 

[wilecoyote]

Re: Help a n00b with reading pressure signs

I can answer only about CCI BR on my .308 700: if I'm sure isn't a bolt problem,I don'like see cratered primers_ I don't think it's really dangerous,but for sure something goes under stress,and if I can avoid this,I'm happier_

 

[Twitch2120]

Re: Help a n00b with reading pressure signs

i dont see much wrong with your loads. the primer flow can just be because your firing pin is a little loose in the hole. primer has room to expand into it. they certainly dont seem flat by any stretch. if i can find a 30-06 case i shot in a garand that was over pressure ill post a pic. besides ripping the rim and sticking in the chamber it has a real flat primer.

50 grains of imr 4895 they said, it'll be fun they said!