Case trimming before or after resizing

[F. Guffey]

I have seen dozens of 7.62 NATO fired cases that were ejected from 30-06 Garands. Shoulders were about 1/16" long.

One guy had 18 on the ground around him before his score keeper mentioned it.

And the next response you will be calming the virtues of centering the bullet in the throat and the importance of perfect sizing the case like a bench rester etc. etc.

And I said I want all the bullet hold I can get; there are a few reloaders on this forum that understand 50 pounds of hold for me is a good day. And then you went off on the dissimilar metals. Many years ago members of this forum got the bullet hold up to 500 pounds and they blamed it on cold welding. I guess it was two years before that one went quite.

At the same time we had a member that fired 4 rounds before he examined the fired cases. He thought it strange that all the necks were missing. He remove the bolt for an inspection. He found the neck of the case still in rifle. He assumed the neck separated when fired and was blown out next the next round was fired.

F. Guffey

[Unclenick]

The Garand Bart saw digesting .308s certainly has a push feed and snap-over extractor. I looked at the case measurements and tolerances and the diameter of the .308 Winchester's average case body/shoulder intercept would meet the sides of the taper in the average .30-06 chamber at about 1.544 inches from the breech face and jam into it for a distance of 0.010 inches if the bolt face was in contact with the head. Instead, the extractor would push it forward, but I surmise that shoulder wedging jammed hard enough to cause the Garand extractor to be able to snap over the rim. That had to have happened for the cartridges to fire. If it were in front of the extractor, the firing pin would not protrude enough to fire it.

[cw308]

I'm sure we can all come up with scenarios on how something can happen . Why do some question about a members post when the are telling what they saw . What would be the purpose for someone to post it if it wasn't true .

[Bart B.]

Originally Posted by cw308

Why do some question about a members post when the are telling what they saw.

Same reason members of The Flat Earth Society question the astronauts about their trip to the moon and their photo of the round earth. They do not believe it is possible because it contradicts their understanding of what earth and moon are physically.

Many myths exist about firearms and ammo.

[F. Guffey]

I'm sure we can all come up with scenarios on how something can happen . Why do some question about a members post when the are telling what they saw . What would be the purpose for someone to post it if it wasn't true .

You were not here the first time this one went around. The first CSP as in Culver shooting page had Culver shooting the M1. He was the first to report firing the 308W ammo in the 30/06 chamber. At that time there were questions like; "HOW CAN THAT BE?". I said the 308 W is larger in diameter at the case body/shoulder by .014" than the 30/06 chamber meaning the case of the 308W head space on the case body/shoulder juncture. Members wanting to claim everything got a new start when the archives of the first CSP were dumped.

But Culvers writings are still available on the resurrected re-resurrected forum.

And then there is the claim the firing pin shortens the case from the shoulder to the case head .005" when the case shoulder of the case collides with the shoulder of the chamber. I have asked how can that happen? I have chambered 8mm57 ammo in my 8mm06 chambers; after firing I have ejected cases with a hint of a shoulder. My cases do not have head space but the 30/06 chamber is .127" longer from the shoulder to the bolt face than the 8mm57 case when measured from the shoulder to the case head. The 8mm57 will not head space on the case body shoulder juncture. And if the firing pin drove the case forward until the shoulder collided with the chamber shoulder the case would still have a neck and shoulder and for most that has got to be a mind boggling thing.

F. Guffey

[F. Guffey]

Many myths exist about firearms and ammo.

You claim you shoot 308 W cases 45 times with full loads. And now you have refined your response/claim ab adding trimming occasional; and in the beginning I asked you what the case weighed when you started and what did the case weight when finished. And then you claimed the case is shorten by firing pin impact by as much as .005 from the shoulder of the case to the case head.

I claimed a box of ammo came to me with 15 fired cases with 5 failed to fire rounds. The shooter purchased a new rifle with two new over the counter boxes of R.P. green boxes ammo.

The 5 failed to fire rounds were struck by the owner of the new rifle 3 times and then anyone else with a 30/06 rifle was given the opportunity to have a go at it. In all the primers were struck 7 times +. I refuse to believe it was a miracle when I measured the length of the failed to fire cases from the datum/shoulder to the case head and with all of the abuse handed out by the firing pins the case did not shorten .001" between the datum/shoulder to the case heade.

And then? I pulled the ' 5 failed to fire rounds' and was impressed the precision loading of Remington. I removed the primers expecting to see duds or dust, that did not happen. I installed the primers back into the same cases they were removed from; and then I chambered the cases one at a time into one of my 'killer firing pin' rifles and pulled the trigger.

The report was loud, all 5 primers busted off, not one of the primers backed out and not one of the cases got shorter from the shoulder/datum to the case head.

It all started when I received a phone call from a firing range; the caller wanted to know what was wrong with RP Ammo. I told them to call Remington, I was helpful because I told them I did not know and then I informed them Remington ammo has the phone number on the box. And still, the ammo shows up in the afternoon.

The shooter that brought the ammo over went home and started a search for tools and gages. A few days later he wanted to know what brand. I informed him tools were available but if he wanted stuff like the tools we used he will have to make it.

F. Guffey

[Bart B.]

Guffey says the first CSP as in Culver shooting page had Culver shooting the M1. He was the first to report firing the 308W ammo in the 30/06 chamber.

Where was Major Culver in early 1964 when such ammo was first fired in Garands on a rifle range near San Diego, California testing it then reported by the testing facility?

[cw308]

1964 I finished High School , why would anyone spend time testing 308 ammo in a 30-06 M1 Garand . I wouldn't try shooting a 6.5 CM in my Rem 700 308 .

[Bart B.]

Originally Posted by cw308

1964 I finished High School , why would anyone spend time testing 308 ammo in a 30-06 M1 Garand . I wouldn't try shooting a 6.5 CM in my Rem 700 308 .

In early 1964 when the USN Small Arms Match Conditioning Unit got its first batch of Garand barrels from Springfield Armory, MA, rifled and chambered for 7.62 ammo, they knew that some thought all rifles issued for matches thereafter were chambered for 7,62 ammo. And match directors would not always verify competitors were issued the right ammo for the rifle they would use.

Chamber adapters were made to fill the space between chambered 7,62 ammo shoulder and 30-06 chamber shoulder. Sometimed the adapter came out with the ejected case and the next chambered round was not full forward. Tests proved no problems, but accuracy was poor so adapters were no longer used. Another batch of 7.62 Garand barrels were obtained in 1965.

So tests shooting 7.62 ammo in 30-06 Garands were made.

[cw308]

Thanks B for the explanation .

[Reloadron]

What Bart is getting at was a pretty good try but also a dismal failure and for several reasons including that the bullet from a 7.62 cartridge had to travel a good 1/2 inch before it found any rifling to mate with. Navy .308 Garand Conversion is a good read on the subject and testing of the concept. The link also includes the original test report, dated October 30, 1964. While none of this has anything to do with case trim before or after sizing it is interesting stuff from days of yore.

Now as to the trim thing and assuming full length sizing of for example a .308 Winchester case. Standard resizing, nothing like case forming using special dies made for such applications. Case resizing using just as an example RCBS FL Die Set 308 Win P/N: 15501 to remove any guess work or assumptions.

I start with 3 cases of once fired brass. My guess based on the numbers they were fired in a machine gun. Years ago I bought several thousand rounds of this WCC 10 brass and it has worked well for me. Anyway, all three pieces measured base to shoulder datum 1.638" and had a cartridge overall length measurement as follows:
#1 2.024"
#2 2.013"
#3 2.022"

Following resizing here is what I got:
#1 2.032
#2 2.023"
#3 2.030"

All 3 cases now have a base to shoulder datum measurement of 1.630" so during resizing while the case head to shoulder datum measurement did decrease as we should expect the case overall length certainly increased. Now is when I would trim all the brass to a uniform case length of 2.005". Had I trimmed and then resized I would not get the uniformity I want in my loads. Anyone can easily try this and get a few numbers.

Ron

[Bart B.]

All the 'smiths in the USN shop thought the chamber insert was a bad idea to start with. Several such Garands were used by Recruit Training Command at the nearby Camp Elliott range for marksmanship training. Scores shot by 30-06 Garands were much better.

The USN team support van at the 1990's Nationals were sometimes asked by civilians to fix their Garands that would not handle the ammo they got to shoot in it. One brought in his just bought Garand to find out why 30-06 ammo would not chamber. He learned to use 308 ammo instead.

[hounddawg]

I wouldn't try shooting a 6.5 CM in my Rem 700 308

a .243 or a .260 would fire just fine CW, won't get any spin on the bullet but it will safely fire. Until you get to the neck the cases are identical. I have been using a .308 seating die for my .260 Rem for 5 or 6 years now and make sub .5 MOA ammo with it

edit - the bolt will not close on a Creedmoor

what was this thread about again ?

[cw308]

I size and trim after every firing for my 308 . I keep my trim length to 2.010 , by doing it every firing it's more like a clean up , very little is removed. dawg , I have my one and only 308 and dies to match , didn't know you could use the same seating die with similar calibers .

[Bart B.]

Originally Posted by cw308

I have my one and only 308 and dies to match , didn't know you could use the same seating die with similar calibers .

30-06 cases can be neck only resized with a 308 Win sizing die.

[hounddawg]

didn't know you could use the same seating die with similar calibers

been using a Forster Micrometer die for .308 Win for seating bullets for my .260 Rem for years now, ever since I decided to try the cartridge. I was on a tight budget when I rebarreled from .308 and decided to give it a try and it works great. So much for the armchair engineers theory that for low run out the case neck has to be held in a deaths grip by the seating die. The case body and shoulder for the .243 Win, the .260 Rem and the .308 are identical

[cw308]

Bart B
I rather use the dies for each caliber , I can see how a 308 sizing die could be used to size the neck but wouldn't think to use my 308 seating die to seat the bullet of 243 or a 260 with a 308 seater . Maybe if I had a safe full of different calibers I may try to find ways to cut down the die inventory . I'm a one rifle guy , makes things simple. Be Well , glad your back .

Chris

[Bart B.]

cw308,

What difference does it make the seater has a few thousandths or hundredths inch clearance to case neck and bullet if case neck is well centered on case shoulder and body?

[Unclenick]

This comparison of seating dies may be interesting to some. The red lettering and underlining were added by the vendor hosting it and were not part of Salazar's orignial article.

[cw308]

Bart B
I have no idea how much of a difference it would make , I only use one seating die , the Redding Competition Seating Die is for my 308 and I'm happy with it .

[Bart B.]

Originally Posted by Unclenick

This comparison of seating dies may be interesting to some. The red lettering and underlining were added by the vendor hosting it and were not part of Salazar's orignial article.

Salazar's gauge's rear reference point is at the pressure ring on the case that typically is against the chamber. Any out of round there will move the bullet tip half to a third as much in the opposite direction. The front reference point on the case is the body right behind the case shoulder that typically does not touch the chamber. Any out of round there couples to that at the pressure ring.

Full length sized bottleneck cases headspacing on their shoulders center their shoulder in the chamber shoulder when fired, their case body is typically against the chamber only at their pressure ring. Case necks usually don't touch chamber necks

No commercial runout bullet runout gage holds such cartridges like they are when fired. A 308 Win perfectly straight cartridge is slightly crooked in the chamber when fired; for each .001" off center the case head is, the bullet tip is almost .001" off center in the bore. The further the dial indicator is from the front reference, the more runout the bullet will have.

[Unclenick]

Originally Posted by Bart B.

A 308 Win perfectly straight cartridge is slightly crooked in the chamber when fired; for each .001" off center the case head is, the bullet tip is almost .001" off center in the bore.

Yes, but it needs to be pointed out that mislocation tends to be consistent shot to shot. Both A. A. Abattielo's old test of 42 lots of 30-06 NM ammo measured for runout and Harold Vaughn's tests showed that if the off-axis error is located in the same place for every shot, the error sends the bullets to the same spot.

Have you looked at how far off the pressure ring is in a resized case? I don't expect perfect roundness from resizing but haven't checked that particular value myself.

If you could assume perfect case body symmetry, this is how measuring the supports (small circles) in different locations would measure the same cartridge:

[F. Guffey]

And then there was what most considered an old man at a shooting contest. He did not show up with a rifle, he did not bring his ammo meaning he did not reloade his ammo. So? His plan was to use a loaner rifle and he was going to their ammo.

If ever thing had ISO ISO controls it would not have mattered what rifle he used and it would not have mattered what rifle he used. And then he got a late start because the loaner rifle was a piece of junk, His host took him to an arsenal in an attempt to select another rifle. He choose a rifle out of a rack and returned to the contest. He did not complain about the ammo and the alignment of the bullet and case and then there could have been that mean old extractor well try to understand he did not blame every thing, he blamed the rifle.

By the end of the day he impressed most and the shooter that was his competition had his own rifle and ammo.

And then by the rules if he won he was to be given the rifle, it was not like the Oklahoma Championship rings that that arrived 21 years late but they had to mail him the rifle. That was no way to treat an old man.

F. Guffey

[F. Guffey]

Yes, but it needs to be pointed out that mislocation tends to be consistent shot to shot. Both A. A. Abattielo's old test of 42 lots of 30-06 NM ammo measured for runout and Harold Vaughn's tests showed that if the off-axis error is located in the same place for every shot, the error sends the bullets to the same spot.

That sounds like the shooter/reloader/ writer of articles about anything gun related. He purchased 500 cases in what could be considered one lot from one manufacturer. After receiving the cases he started sorting and separating and then firing. After firing he sorted and separated and matched up he started over.

It must have been a long Boring story because I have never found one reloader/shooter that read the article. Finally when finished he found 46 of the cases that were perfect and the other cases that were culled almost gave the same accurate results when indexed in the chamber.

I have all the respect in the world for those old folks.

F. Guffey

[F. Guffey]

Forgive: He did not fix the gun.

F. Guffey