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My 308 always shows high pressure signs.


Justintoxicated

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So I finally got back to the range, this time with the chronograph and two kinds of factory ammo (Federal 168gr match, and Nosler 168gr Match ammo).  The federal shot decent and the primer cups looked about the same as my reloads.  Flattened primer and some cratering from the firing pin.  The Nosler ammo was a problem, the primers actually fell out of the brass and the anvil got jammed up in the action near the chamber, almost had to mortar the thing to get it unstuck.

 

Velocity from the 168's Federals was about 500fps faster than my 43gr loads for the 175 SMKs.  I need to find my paper to give the average but my reloads all read around 2620-2630 fps.

 

Should I start looking for a different Barrel?   Maybe the rainier arms ultra match is just junk.

Edited by Justintoxicated
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^^^^ Now that they're done.....

I think you should contact Rainier about this, they are really good with customer service and stand behind their product, so if you have a bad one, I would assume they will take care of you.

Have you headspaced it? I ask this without going back through the thread, thinking that if it's that you can send the back the barrel and maybe send your bolt too for them too headspace to a barrel

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So I finally got back to the range, this time with the chronograph and two kinds of factory ammo (Federal 168gr match, and Nosler 168gr Match ammo).  The federal shot decent and the primer cups looked about the same as my reloads.  Flattened primer and some cratering from the firing pin.  The Nosler ammo was a problem, the primers actually fell out of the brass and the anvil got jammed up in the action near the chamber, almost had to mortar the thing to get it unstuck.

 

Velocity from the 168's Federals was about 500fps faster than my 43gr loads for the 175 SMKs.  I need to find my paper to give the average but my reloads all read around 2620-2630 fps.

 

Should I start looking for a different Barrel?   Maybe the rainier arms ultra match is just junk.

2620-2630 ,is that with 175SMK's ?

 

Did you chromo the Noslers ? If so what was the Vol. ? The primer blowing out is not a good thing .

 

 Heavy bullets tend to flatten the primers.

 

Barrel , well that's a difficult diagnosis , making a cast the chamber will tell what the true dimensions are. It may have a tight chamber ?

 

I have seen or heard of this , or some thing like it before , just don't remember the cause or what was found.

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2620-2630 ,is that with 175SMK's ?

 

Did you chromo the Noslers ? If so what was the Vol. ? The primer blowing out is not a good thing .

 

 Heavy bullets tend to flatten the primers.

 

Barrel , well that's a difficult diagnosis , making a cast the chamber will tell what the true dimensions are. It may have a tight chamber ?

 

I have seen or heard of this , or some thing like it before , just don't remember the cause or what was found.

 

Yea 175 SMKs with 43gr load, with 40gr I was at 24xx (I'll edit this post later with the exact average).  Keep in mind this is from a 24" barrel though.  The 155gr Palmas were also flattening primers.

 

I did not chronograph the Noslers due to not wanting to shoot anymore of them.  They were the first thing I shot because I was finally able test out some factory ammo.  I was able to chrono the federals because a buddy traded me for a few noslers once I had the chronograph setup.

Edited by Justintoxicated
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If head space was good , I find it odd that there would be something wrong with the chamber , but as said , a chamber casting would be the true gage of what its spec's are . Throat could be wrong or not enough . The barrel bore may even be wrong . Hard to say  The fact that different bullet configurations are producing the same results is troubling.

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  • 3 months later...

Not sure if it's the primer (F 210), but I did a set of light loads with 168gr A-Max and 42g (minimum recommended load) of Varget. Shots were landing 1.5 mil low + 1.5 mil left of my regular loads (42.5gr I-4064, 175gr BTHP) . Funny thing is the primers all looked cratered with the minimum load....is it overpressure?

Edited by shibiwan
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You're comparing Apples and Hammers.

 

Two completely different projectiles, brother.  Getting a 1.5mil difference shouldn't be a concern between those two.

 

Yeah, I know... the projectiles are significantly different, but I like my hammers. I'm just wondering why I'm getting overpressure signs on a light load.

 

Loaded 50 more A-Max tonight - this time took it down to 41.5 gr. Hope that fixes it.

Edited by shibiwan
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  Were the primers overly flattened ? Showing little or no distinction from the edge of the primer & its pocket ?

 

  Low pressure loads may show a slightly cupped primer indentation , but not a flattened primer, still having a distinct out line of the primer & its pocket , rounded primer edges where it meets the pocket ( like unfired) . the primer will still be flattened some what ,but not to the point where you can't perceive its edge. Its the overly flattened primer that looks like it has flowed into the edges of the primer pocket, that are a sign of over pressure, of course that will also have a pronounced firing pin indentation cratering.

 

 Different bullet manufacturers & weight bullets may need different COL's because of the various bullet olgive's . You can have one manufactures bullet , that will be ok , than the same weight bullet from another manufacturer , could show pressure signs .Going to different weight bullets , even with the same manufacturer , may have a different Olgive or in a different place with in the length of the bullet & may need a different COL.

 

 You could also get int to how different manufacturers make there bullets , harder jacket , softer jacket , same with the lead core . All will show different pressure signs , with the same loading . Then you have the solid Copper bullets  , which are a different beast & in my experience , can have a larger powder load with out showing the same pressure signs as a lead cored bullet.

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Mostly cratering, enough to leave a ridge around where the firing pin strikes. I don't see that in the factory loads (which to me, feels hotter).

 

I adjust the COL for different projo's to ensure that the lengths are correct, as I've compared the profile of the different bullets. 

 

 

On a side note, I've regularly loaded Barnes Match Burners (175gr) and have had excellent results, perhaps a little better than the SMK's. Always wanted to load some TTSX but I can't seem to find them anywhere right now.

Edited by shibiwan
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  The 150 gr. TTSX 308's are very good shooters , I load some for a couple of hunter friends ( 30'06 ) . I have also loaded some of there Tac X 168 gr bullets & had mix results & too dam expensive to play around with , when I know what results I can get with bullets half the cost . I even had problems loading them , had to email Barne's .

 

  I also load Hornady SST's ( 30'06, 7MM-08 & 270 ), they seem to be a better grouping bullet & the guys I load them for are very pleased with the end result on Deer.

 

 I think you will find that every chamber & barrel are different & one may or may like a certain load , bullet , powder or primer . Just what I have found throughout the years. 

 

 Have you posted photos of the offending ammo's spent cases ?

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If you're seeing any pressure signs with regular bullets, my experience has been that it will get worse using TTSX heads.  I think it happens because they're longer for the weight so you lose some space in the case.  For example, 48.0 of CFE223 with a 168 Sierra GameKing is not a compressed load, but with a 168 TTSX it is.

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  The problem I had loading IMR 4064 with the Tac X bullet & with loading data from Barnes , the powder was so compressed , the bullet would stick to the seating stem or pop the bullet back out , because of the different shape of the Tac X bullet . Emailed Barnes &  was told to polish the inside of the bullet cavity of the seating stem , which cured it , but I could not get them to print well with even WC 846 , which had plenty of room in the case. Just too expensive to work out the the right combo.

 I think if using the WC846 , which is a pull down ball powder , you will not have a problem with it or a similar ball powder.

 

The loads I spoke of in my previous post are all loaded with IMR 4064 & none are compressed loads.

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  • 2 weeks later...

Just from my past experiences I'll try and give a little here. My LR308 I also used the JP BCG and seems just fine to me. I think you probably eliminated that as a contributor, I have not read thru all the posts here.

I have for my LR used 168 smk, 168 & 178 amax, 180 nosler silver tip and a few others. I have used IMR 4064, H4895, CFE-223 & Varget in my experimenting. Primers - WLRP, CCI, Federal. Win brass, Hornady brass & Remington.

From combo's of these components and powders there was one outlier that always seemed to get in my way, and disappointingly so. That was the Varget. For one thing I could not get rounds to group as well as with the other powders. It seemed like my brass would be beaten up more so than with the other powders, even the CFE-233 that I went crazy with, I mean I am crazy about it it did so well with groupings and nice velocities out of the 16" JP Supermatch. I could obtain 2700 fps with CFE and 168 amax. Believe me I studied that brass and primers over and over and it was no different than my best IMR 4064 solution with the amax. They were, with the CFE-223 & 168 amax, powder weights of over 47 gr.

I never finished my experiments, I got in a funk that I haven't gotten out of yet.

I guess my point is, I don't like the Varget.

This is just MY experience. As the CFE is pretty impressive for velocity gains, I highly recommend IMR 4064, tried and true. H4895? Why not? H4895 my best groups.... My experience.

Edit: guys I must apologize. And I must correct statements I made above regarding cfe-223. Yes I could achieve 2700 fps with a 168 amax. But I remember now it did beat up my brass somewhat. So I started trying it with 178's amax and 180's nosler. That is when it shined in my case. It grouped well and got those heavies out the 16" faster and the brass did well too. I will not quote a charge weight here. Actually my memory isn't serving me well about that. The data is packed away for now. Again I'm am sorry and I'm glad I at least belatedly remembered.

Edited by NoFail
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