What should I look for on the rifle to be sure it's not damaged from 50 rounds that were fired and primers are pretty flattened? They extracted fine and didn't feel "hotter" than other rounds fired the same day. The brass looks OK except for the flattened primers. The rounds were reloads I got from someone who knows what they are doing. The rifle is a Remington 40X in 7.62 Nato. According to the paper in the box they were the same as the loads I made myself which were 150gr bullets with 43gr of Varget. None of my reloads had the flattened primers and as I said they all felt and sounded the same when fired. (I know that's not an accurate way to tell anything but I've saved myself headaches before by noticing a difference)
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Overpressure signs on 50 rounds. Rifle Damaged???
- Thread starter oneshot onekill
- Start date
Re: Overpressure signs on 50 rounds. Rifle Damaged???
150 gr bullets and ONLY 43 gr of Varget is a recipie for secondary pressure--that is it is a very light load. Too light for its own good.
Secondary pressure is a phenomonom where there is insufficient pressure to accelerate the bullet all the way down the bore. As the bullet decelerates due to lack of pressure, the expanding shock wave from the burn reaches the back of the bullet and is reflected. As this shock wave traverses the mixture, it detonates any unburned powder and massively increases the pressure. See http://www.shootingsoftware.com/pressure.htm
I had similar issues with 43.6 gr Varget and 155 SMK 2155s. I am currently using 47.8 gr Varget and 155 Scenars.
99.44% the rifle is just fine, just move back up to normal pressure range.
150 gr bullets and ONLY 43 gr of Varget is a recipie for secondary pressure--that is it is a very light load. Too light for its own good.
Secondary pressure is a phenomonom where there is insufficient pressure to accelerate the bullet all the way down the bore. As the bullet decelerates due to lack of pressure, the expanding shock wave from the burn reaches the back of the bullet and is reflected. As this shock wave traverses the mixture, it detonates any unburned powder and massively increases the pressure. See http://www.shootingsoftware.com/pressure.htm
I had similar issues with 43.6 gr Varget and 155 SMK 2155s. I am currently using 47.8 gr Varget and 155 Scenars.
99.44% the rifle is just fine, just move back up to normal pressure range.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
Man... Not doubting your expertise but the .308 Manual I have says 44.something is the MAX for 150gr and Varget. That's why I was worried. I was afraid it was so close to max that it may have been mis-measured and grossly over-loaded. I feel much better but moving UP scares the crap out of me! LOL!!!
Man... Not doubting your expertise but the .308 Manual I have says 44.something is the MAX for 150gr and Varget. That's why I was worried. I was afraid it was so close to max that it may have been mis-measured and grossly over-loaded. I feel much better but moving UP scares the crap out of me! LOL!!!
Re: Overpressure signs on 50 rounds. Rifle Damaged???
150 GR. NOS BT Hodgdon Varget .308" 2.800" 44.0 2788 43,300 CUP 47.0C 2937 50,300 CUP
I show 47 grains for a 150gr bullet
168 GR. SIE HPBT Hodgdon Varget .308" 2.800" 42.0 2520 41,200 CUP 46.0C 2731 50,600 CUP
and 46gr for a 168gr bullet
That is from Hodgdon powder site.
hodgdon loads http://data.hodgdon.com/cartridge_load.asp
150 GR. NOS BT Hodgdon Varget .308" 2.800" 44.0 2788 43,300 CUP 47.0C 2937 50,300 CUP
I show 47 grains for a 150gr bullet
168 GR. SIE HPBT Hodgdon Varget .308" 2.800" 42.0 2520 41,200 CUP 46.0C 2731 50,600 CUP
and 46gr for a 168gr bullet
That is from Hodgdon powder site.
hodgdon loads http://data.hodgdon.com/cartridge_load.asp
Re: Overpressure signs on 50 rounds. Rifle Damaged???
Could have been a multiplicity of things in the loads he makes versus how you do it. However the first one that comes to mind is that if the brass he was/is using has a lower capacity then what you use, such would definitely affect pressure. Checking that's pretty easy. I'm assuming here that you both use the same brand of brass, manufactured more or less about the same time.
Other causes which come to mind as playing a role in this include neck tension, as well as whether or not he turns the necks on the cases he uses. Inside, outside, or both.
Also, different lots of powders of the exact same make can perform differently. Both powder straight from the factory, & or because it was stored differently. Plus a laundry list of other things.
All of that said, odds are the rifle is fine, but if you're truly concerned, have someone real sharp take a look at it. Doing so likely wont turn up anything given your descriptions, but if it gives you peace of mind, that's a big thing.
If you go that route, I'm sure it'd be educational for, & appreciated by many to hear what sort of things the smith/metalurgist did to check the weapon's integrity. Plus, were it me, I'd take along a handful of the fired cases in question, as well as some of those from your private stock. So that he might compare the two.
Any chance you happened to chrony both loads? Or in lieu of that, did your point of impact change much between your loads & his? If so, then it's easy to tell if something's amiss with regards to the 2 different loads.
Ah, & please forgive me if I'm going over stuff which you've already ruled out, or that you learned a long time back. Not everyone on here of course, has the same levels of knowledge when it comes to reloading.
Could have been a multiplicity of things in the loads he makes versus how you do it. However the first one that comes to mind is that if the brass he was/is using has a lower capacity then what you use, such would definitely affect pressure. Checking that's pretty easy. I'm assuming here that you both use the same brand of brass, manufactured more or less about the same time.
Other causes which come to mind as playing a role in this include neck tension, as well as whether or not he turns the necks on the cases he uses. Inside, outside, or both.
Also, different lots of powders of the exact same make can perform differently. Both powder straight from the factory, & or because it was stored differently. Plus a laundry list of other things.
All of that said, odds are the rifle is fine, but if you're truly concerned, have someone real sharp take a look at it. Doing so likely wont turn up anything given your descriptions, but if it gives you peace of mind, that's a big thing.
If you go that route, I'm sure it'd be educational for, & appreciated by many to hear what sort of things the smith/metalurgist did to check the weapon's integrity. Plus, were it me, I'd take along a handful of the fired cases in question, as well as some of those from your private stock. So that he might compare the two.
Any chance you happened to chrony both loads? Or in lieu of that, did your point of impact change much between your loads & his? If so, then it's easy to tell if something's amiss with regards to the 2 different loads.
Ah, & please forgive me if I'm going over stuff which you've already ruled out, or that you learned a long time back. Not everyone on here of course, has the same levels of knowledge when it comes to reloading.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
For a 150gr bullet in a .308 my Sierra manual lists 44.8 grs of Varget as max and 41.4grs as starting . Same setup in my Lyman manual states 47grs max and 42.5grs minimum.
That being said I don't pay much attention to primer flattening as I get it on even mild loads. I pay more attention to ejector flow, bolt swipe, primer cratering, and sticky bolt lift.
I'm sure your rifle is fine if primer flattening is all you have as far as pressure signs.
For a 150gr bullet in a .308 my Sierra manual lists 44.8 grs of Varget as max and 41.4grs as starting . Same setup in my Lyman manual states 47grs max and 42.5grs minimum.
That being said I don't pay much attention to primer flattening as I get it on even mild loads. I pay more attention to ejector flow, bolt swipe, primer cratering, and sticky bolt lift.
I'm sure your rifle is fine if primer flattening is all you have as far as pressure signs.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">If using Hodgdon powders then look at Hodgdon's site for load data. Some manuals, like Sierra, are very conservative. </div></div>
Yep. The Sierra book is an absolute joke.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">If using Hodgdon powders then look at Hodgdon's site for load data. Some manuals, like Sierra, are very conservative. </div></div>
Yep. The Sierra book is an absolute joke.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
I'd say it's probably impossible to make a definitive determination regarding unsuitable pressures in your particular instance.
I'd approach it a different way. Since bolt lift was not significantly, noticeably excessive, and extraction was uncomplicated, I'd be inclined to think that you've escaped damage.
Now go forth, and sin no more...
Greg
I'd say it's probably impossible to make a definitive determination regarding unsuitable pressures in your particular instance.
I'd approach it a different way. Since bolt lift was not significantly, noticeably excessive, and extraction was uncomplicated, I'd be inclined to think that you've escaped damage.
Now go forth, and sin no more...
Greg
Re: Overpressure signs on 50 rounds. Rifle Damaged???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">If using Hodgdon powders then look at Hodgdon's site for load data. Some manuals, like Sierra, are very conservative. </div></div>
Yep. The Sierra book is an absolute joke. </div></div>
Rob01-I agree that some of Sierra's data is quite conservative.
Downzero- I have read some of your other posts. I'm about as impressed with your know-it-all asshole attitude(specifically the thread about the Whidden bedding block) as you are with Sierra's manual.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Downzero</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">If using Hodgdon powders then look at Hodgdon's site for load data. Some manuals, like Sierra, are very conservative. </div></div>
Yep. The Sierra book is an absolute joke. </div></div>
Rob01-I agree that some of Sierra's data is quite conservative.
Downzero- I have read some of your other posts. I'm about as impressed with your know-it-all asshole attitude(specifically the thread about the Whidden bedding block) as you are with Sierra's manual.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grounds Keeper</div><div class="ubbcode-body">Could have been a multiplicity of things in the loads he makes versus how you do it. However the first one that comes to mind is that if the brass he was/is using has a lower capacity then what you use, such would definitely affect pressure. Checking that's pretty easy. I'm assuming here that you both use the same brand of brass, manufactured more or less about the same time.
Other causes which come to mind as playing a role in this include neck tension, as well as whether or not he turns the necks on the cases he uses. Inside, outside, or both.
Also, different lots of powders of the exact same make can perform differently. Both powder straight from the factory, & or because it was stored differently. Plus a laundry list of other things.
All of that said, odds are the rifle is fine, but if you're truly concerned, have someone real sharp take a look at it. Doing so likely wont turn up anything given your descriptions, but if it gives you peace of mind, that's a big thing.
If you go that route, I'm sure it'd be educational for, & appreciated by many to hear what sort of things the smith/metalurgist did to check the weapon's integrity. Plus, were it me, I'd take along a handful of the fired cases in question, as well as some of those from your private stock. So that he might compare the two.
Any chance you happened to chrony both loads? Or in lieu of that, did your point of impact change much between your loads & his? If so, then it's easy to tell if something's amiss with regards to the 2 different loads.
Ah, & please forgive me if I'm going over stuff which you've already ruled out, or that you learned a long time back. Not everyone on here of course, has the same levels of knowledge when it comes to reloading. </div></div>
To tell you the truth, I've learned a lot from this post.
The loads in question are a few years old and mine were made last week. The brass is different brands. Neither of us turn our necks. He didn't specify what primers were used. Given these discrepancies alone I'm just gonna call it good. As far as a chronograph goes, I don't have one but my brother does so I'll borrow it next time out.
I also noticed after looking at one of the rounds in question that was unfired that the primers don't appear to be seated all the way in. They're pretty much flush but I believe they should actually be a little deeper than flush IIRC.
After reading all of the great responses here I think everything is OK. Thanks to all who participated!
John
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grounds Keeper</div><div class="ubbcode-body">Could have been a multiplicity of things in the loads he makes versus how you do it. However the first one that comes to mind is that if the brass he was/is using has a lower capacity then what you use, such would definitely affect pressure. Checking that's pretty easy. I'm assuming here that you both use the same brand of brass, manufactured more or less about the same time.
Other causes which come to mind as playing a role in this include neck tension, as well as whether or not he turns the necks on the cases he uses. Inside, outside, or both.
Also, different lots of powders of the exact same make can perform differently. Both powder straight from the factory, & or because it was stored differently. Plus a laundry list of other things.
All of that said, odds are the rifle is fine, but if you're truly concerned, have someone real sharp take a look at it. Doing so likely wont turn up anything given your descriptions, but if it gives you peace of mind, that's a big thing.
If you go that route, I'm sure it'd be educational for, & appreciated by many to hear what sort of things the smith/metalurgist did to check the weapon's integrity. Plus, were it me, I'd take along a handful of the fired cases in question, as well as some of those from your private stock. So that he might compare the two.
Any chance you happened to chrony both loads? Or in lieu of that, did your point of impact change much between your loads & his? If so, then it's easy to tell if something's amiss with regards to the 2 different loads.
Ah, & please forgive me if I'm going over stuff which you've already ruled out, or that you learned a long time back. Not everyone on here of course, has the same levels of knowledge when it comes to reloading. </div></div>
To tell you the truth, I've learned a lot from this post.
The loads in question are a few years old and mine were made last week. The brass is different brands. Neither of us turn our necks. He didn't specify what primers were used. Given these discrepancies alone I'm just gonna call it good. As far as a chronograph goes, I don't have one but my brother does so I'll borrow it next time out.
I also noticed after looking at one of the rounds in question that was unfired that the primers don't appear to be seated all the way in. They're pretty much flush but I believe they should actually be a little deeper than flush IIRC.
After reading all of the great responses here I think everything is OK. Thanks to all who participated!
John
Re: Overpressure signs on 50 rounds. Rifle Damaged???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">
Flattened primers with no other indicator is more commonly a sign the case shoulder has been set back too far for the chamber than it is of any excess pressure. </div></div>
+1 this is probably the case, especially if they were reloaded by someone else.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Fuzzball</div><div class="ubbcode-body">
Flattened primers with no other indicator is more commonly a sign the case shoulder has been set back too far for the chamber than it is of any excess pressure. </div></div>
+1 this is probably the case, especially if they were reloaded by someone else.
Re: Overpressure signs on 50 rounds. Rifle Damaged???
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: McCrazy</div><div class="ubbcode-body">
That being said I don't pay much attention to primer flattening as I get it on even mild loads. I pay more attention to ejector flow, bolt swipe, primer cratering, and sticky bolt lift.
I'm sure your rifle is fine if primer flattening is all you have as far as pressure signs.</div></div>
i agree
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: McCrazy</div><div class="ubbcode-body">
That being said I don't pay much attention to primer flattening as I get it on even mild loads. I pay more attention to ejector flow, bolt swipe, primer cratering, and sticky bolt lift.
I'm sure your rifle is fine if primer flattening is all you have as far as pressure signs.</div></div>
i agree
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