Should I do it?

KnotRight

KnotRight

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With the issue that I have with my 308 brass some being really short, I was thinking about pulling all the 308 that I have loaded and check the case length. I must have close 600 - 700 rounds loaded. If I do, I think that I am going to do it by powder that is loaded. I really like Varget and have some on hand. I know that you are not suppose to mix lots of the same powder but for what I am doing and with what I am shooting them out of I do not think it would matter. Will not start the ladder reloading test until the new dies comes in on Monday or Tuesday.
Also. I am using a RCBS collet bullet puller and when I run the pulled cases through the resizing die, would you take out the depriming pin. I do not see any reason to deprime them.
 
As for the cases being short, are you talking about dimension to the shoulder, or to the case mouth? Dimension to the case mouth is not critical, they can still be fired, but could cause slight variation in neck tension that might affect accuracy in precision loads.

Yes, you can remove the decapping pin on most dies. With the Lee dies, the pin is part of the expander and can’t be removed. You can remove the whole expander if you intend to use a separate mandrel expander.

There are people that take the same powder from different lots and blend them together, to get one large lot of the same consistency. Start low and work up, like you would with a new powder. The only downside would be if one of the lots ends up being recalled for some reason.
 
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Toprudder said:
As for the cases being short, are you talking about dimension to the shoulder, or to the case mouth? Dimension to the case mouth is not critical, they can still be fired, but could cause slight variation in neck tension that might affect accuracy in precision loads.
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TR, the OAL of the CASE is what has me concern. The SAMMI max is 2.015 and I have some that are 1.950. That has to effect the pressure in the case (yes neck tension) when fired which I have a feeling giving me such a wide shot string. Any where from 8 to 45 ft/sec. I have the gun zeroed at 100 yards and using the ballistic app, at 500 yards I need to add 4 MOA to the reading on the app. 4 MOA is a huge difference. All powder is weighted and trickled. The only think that I can come back to is the amount of case that is on the bullet.

Open to suggesting. As GoofyFoot2001 said, to pull that many rounds is a lot of work.

I just hate not being able to depend on that gun out to 550 yards.
 
KnotRight said:
Open to suggesting. As GoofyFoot2001 said, to pull that many rounds is a lot of work.
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700 rounds is a LOT to pull.

I don't know if you have already done this, but If you can measure the case length reliably without pulling the bullets, maybe you could group them by case length. Then test a few of each group to see how much variance there is in velocity inside the group, and then also between groups. This may also tell you if the variation is the case length, or from some other reason. If the standard deviation inside each group is good, and the velocity just varies between groups, then you could just use a different dope for each group.

If you only had 100, I would recommend not pulling them, but using them a few at a time for things like fouling shots. But 700 - Dang!
 
@Toprudder I am pulling the rounds that I have in my to go box. Maybe 120 of them. About 80% were below 1.975". It is interesting that the ones that are short looks to be in groups. So when I adjusted the WFT trimmer I must have done all those cases at that time. Also, I am on hold with RCBS because the .30 collet does not work well for 30 cal. BTHP and A-Max bullets. You have to put them too far into the collet to get a good grab on the bullet. When pulled, you have to remove the collet from the holder and put the bullet into a soft jaw vise to get the bullet out of the collet. I want to know if they have a special collet for long nose 30 cal bullets.
 
KnotRight said:
I know that you are not suppose to mix lots of the same powder
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Who told you that? Blending same powder from different lots will get you better consistency for your batch.

Before I pull them I would want to know how they perform. Does the problem show up on paper?

I do not see any reason to deprime them.
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What lube are you using to re-size?
 
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Buy a case gauge. If the headspace is OK, then fire away.

What are you shooting this out of?
 
KnotRight said:
at 500 yards I need to add 4 MOA to the reading on the app. 4 MOA is a huge difference.
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Are you saying that you have a 4MOA variance from round-to-round based on the case length? I have a real hard time buying that.

I ran numbers through both Strelok and Applied Ballistics.

Using my AR10 load of 175gr SMK @ 2331fps and current atmospherics...

2286 fps = 14.5MOA
2331 fps = 13.7 MOA
2376 fps = 13.1 MOA

If you're seeing +/- 45fps from baseline, you're looking at 1.4MOA of variance at most, or roughly 7" at 500yards. Not great for accuracy, but far better than the ~20" that 4MOA represents.
 
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@Tim What I had to do after zeroing the rifle at a 100 yards then heading to the 500 to 550 yard steel, I had to add 4 MOA to what my ballistic app was telling me to add.
My calculator says for 168 Hornady BTHP @ 2675 FT/sec
300 -4.5 -14.2"
400 -7.8 -32.5"
500 -11.5 -60.1"
550 -13.5 -77.8" and I had to add about 4 to the 5 and 550 adjustments.

My app (BulletFlight L2) does not tell be what the velocity is suppose to be at the target range.
 
KnotRight said:
TR, the OAL of the CASE is what has me concern. The SAMMI max is 2.015 and I have some that are 1.950. That has to effect the pressure in the case (yes neck tension) when fired which I have a feeling giving me such a wide shot string. Any where from 8 to 45 ft/sec. I have the gun zeroed at 100 yards and using the ballistic app, at 500 yards I need to add 4 MOA to the reading on the app. 4 MOA is a huge difference. All powder is weighted and trickled. The only think that I can come back to is the amount of case that is on the bullet.

Open to suggesting. As GoofyFoot2001 said, to pull that many rounds is a lot of work.

I just hate not being able to depend on that gun out to 550 yards.
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honestly, anything under max especially a few thousands isn’t gonna matter.

this is a bottleneck cartridge. it’s headspace a off the shoulder not the case mouth.

next, if all the brass is not the same head stamp then you’re gonna have to take that in to effect. as some brass is thicker than others.

moisture content in the powder can have an effect the swing in velocity.

did you weight each projectile? a couple tenths deviation on projectile weight can swing the velocity.

seating depth, jump to the lands, chamber specs, there is so much to take in to account than to worry about a few thousandths on the length to the case mouth.

until you actually shoot and verify what the happens when you pull the trigger, the ballistic app is just an idea.

also, the max trim length is that, max, anything over that and it’s not gonna chamber properly due to the neck spec of the chamber
 
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KnotRight said:
@Toprudder I am pulling the rounds that I have in my to go box. Maybe 120 of them. About 80% were below 1.975". It is interesting that the ones that are short looks to be in groups. So when I adjusted the WFT trimmer I must have done all those cases at that time. Also, I am on hold with RCBS because the .30 collet does not work well for 30 cal. BTHP and A-Max bullets. You have to put them too far into the collet to get a good grab on the bullet. When pulled, you have to remove the collet from the holder and put the bullet into a soft jaw vise to get the bullet out of the collet. I want to know if they have a special collet for long nose 30 cal bullets.
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You might be able to pry the petals of the collet apart some so it will let go of the bullet. I've had to do that on a couple of the collets I have. Take the collet out and use a small screwdriver to spread them apart slightly.
 
Toprudder said:
You might be able to pry the petals of the collet apart some so it will let go of the bullet. I've had to do that on a couple of the collets I have. Take the collet out and use a small screwdriver to spread them apart slightly.
Click to expand...

I called RCBS and told them the problem that I was having and they now make a collet for the 30 cal that is 30-275 (I think that is the number) but when I search the internet, nobody had one in stock.
 
KnotRight said:
TR, the OAL of the CASE is what has me concern. The SAMMI max is 2.015 and I have some that are 1.950.
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backwoodsshooter said:
honestly, anything under max especially a few thousands isn’t gonna matter.
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@KnotRight I have to agree with the statement made by @backwoodsshooter above. I have on many many occasions shortened necks and entire cases to work with certain bullets, in a particular rifle. Many times, far more than what you are talking about above. No effect on pressures, velocity, or anything else. There are far more factors out there that might have more effect that just a shortened neck. I measured just now the difference in a 308, and I don't think you will have any issue, or even be able to measure with confidence any real difference. There are absolutely no safety concerns with pressures, and there won't be any neck tension issues with just a slightly shorter neck. As stated, there are lots of other factors involved that would have more effect.

I most certainly would be shooting and testing these before pulling 500+ of them............. If I could get my hands on a few I could run pressures, I have 308 setup.............But I would need to compare with standard length, and has to be your powder and loads, my powder here is not your powder.......... or primers, or brass or or or...............
 
Whois Bin Farteen said:
Adjust the BC to match your data and verify at a different distance
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Sorry to revive and old thread- that is very interesting. I have some coated bullets without a BC and I'm trying to figure one out. Do I pick a similar BC then zero at one distance and then another (using a chrono for muzzle velocity).
 
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