New Remington - chamber oversize ?

P

pisces

Guest
Hi,
I am reloading my new Remington Model 7 CDL in .17 Rem Fireball, using only moderate charges, and have noticed that fired cases will not slide more than half way into a Redding Neck Sizer die (with the expander ball removed) before jamming - needing ram pressure to go fully into the die.

I was under the impression, as a reloading newbie, that neck sizing did not require the case body to be lubed, just the case neck.

I've measured the diameter at several points on new and fired cases:
New/Fired
At the shoulder: .360 / .366
Mid point between shoulder and rim: .368 / .372
At the widest point of the case body, before the extractor groove: .371 / .373

I'm concerned that, after reading the Redding Neck Sizing Instructions, I may have an oversized chamber. However, I don't really know the significance of "oversize" - is it serious, does it mean out of specification and return to manufacturer or it's a common occurrence with a factory chamber and can be overcome by lubing the case body as well as the case neck ? :confused:

Redding Neck Sizing Instructions extract: The die is designed so that the case is closely aligned and supported along the body but it will not size the body or move the shoulder position unless the chamber is oversize.
 
1st make sure you have a neck die and it is not stamped FL (full length). I don't have a drawing for the .17 but looking at the standard 221 fireball, the dimention @ the body/shoulder junction is showing .361 which may mean the chamber is a bit oversize.
Your measurement of .360/.366 is quite a large measurement variance. Try to measure it more accurately. Set your mics/verniers at .361 and use it as a "feeler" working your way around the neck shoulder junction, removing the case from the tool at each measuring spot, not spinning the case while it is contact with the tool.
Also you can try lubing the entire case (except shoulder) and running it into the die. Remove it and look for shiny spots on the body to see where you are getting contact.
 
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Sorry, maybe I could have been a bit clearer, but the .360/.366 measurements are for new case and fired case diameter measurements respectively taken at the shoulder, not variance.

I've checked the Redding die is marked 17 Rem Fireball NK.

I have used a felt marker on a fired case and run it through the neck sizing die and found that the ink is removed/smeared from about 0.1" below the shoulder to 0.1" above the extractor groove i.e practically the full length of the case body.

My Lee Reloading Manual does not have any data for the .17 Rem Fireball but Quickload, the interior ballistic program, gives .365 at the shoulder and .377 at the extractor groove. So, wouldn't that mean that the fired case dimensions are still within spec' ?
 
how snug are things...??!!!

Do the fired cases go bak in the gun easily or are they snug....after lubing and running them thru the die do they fit better (properly) ...if the die resises the brass to fit the gun ...you are there....Roger
 
pisces said:
Hi,
I am reloading my new Remington Model 7 CDL in .17 Rem Fireball, using only moderate charges, and have noticed that fired cases will not slide more than half way into a Redding Neck Sizer die (with the expander ball removed) before jamming - needing ram pressure to go fully into the die.

I was under the impression, as a reloading newbie, that neck sizing did not require the case body to be lubed, just the case neck.

I've measured the diameter at several points on new and fired cases:
New/Fired
At the shoulder: .360 / .366
Mid point between shoulder and rim: .368 / .372
At the widest point of the case body, before the extractor groove: .371 / .373

I'm concerned that, after reading the Redding Neck Sizing Instructions, I may have an oversized chamber. However, I don't really know the significance of "oversize" - is it serious, does it mean out of specification and return to manufacturer or it's a common occurrence with a factory chamber and can be overcome by lubing the case body as well as the case neck ? :confused:

Redding Neck Sizing Instructions extract: The die is designed so that the case is closely aligned and supported along the body but it will not size the body or move the shoulder position unless the chamber is oversize.
Click to expand...

Some opinions:

(First of all, Roger may be onto something there! ;))

now

-Make sure that the Redding die really is a neck size ONLY die. Redding also sells FL dies with replaceable bushings. Based on your measurements it almost sounds like an "S"-Type full length die. Most telling is the base dimension, I can't see a neck-size only die being only .002 larger than the virginal case.

-You are exactly right about the fact that a neck-size only die should not interfere with the case body at all.

-There is no "safety implication" to the chamber being fat..... it may well in fact BE fat, I've seen factory chambers vary as much as .004 diametrically and dies vary by .003, but this isn't necessarily "bad" nor is it in any way dangerous.

-Were I you I'd try the lube idea, it may be that you've serendipitously LUCKED INTO that most sublime of all situations where you actually have a well fitted full-length resizer! :) Let's proceed by looking at the bright side before we go off sending stuff back eh?


NOW.... whatcha's needs to do is supply some measurements of the case AFTER you've lubed it and run it into the die....

ALSO, rechamber the fired empty and see how it fits back in the rifle's chamber. Spin it, index it and make sure that it's a snug fit. Measure it....

Compare....

You must also come up with a way to measure LENGTH to a datum point so's we can check your shoulder setback..... Have you got a Sinclair Ogive "Nut"?? Or some kind of bushing which will fit over the neck to rest on the shoulder somewhere? Preferably half-way down?

Keep us apprised of your progress but most of all DON'T PANIC! (obscure Arthur Dent ref there :eek:)

al
 
Thanks for all the advice. :)

The fired cases do fit back into the chamber. However, the bolt is a bit harder to close than with a new case. So, I guess it's a snug fit.

The case length remains about the same after the first firing and is about 10 thou less than the max chamber length.

As regards shoulder movement, a fired case shoulder is about 7 thou forward to that on a new case.

I've compared the body dimensions of a fired case, before and after neck sizing, and they are the same. However, a neck sized case still needs a little ram pressure to go back into the neck sizing die. So, I guess the brass in the body of the fired case is springing back to it's pre-neck sizing diameter.

Despite my worries about chamber oversize, the gun shoots good. So it can't be that bad. :)
 
From experience a long time ago with a .22-250 that had a large chamber, if you FL size your cases they'll likely begin failing due to head separations. One thing you could do is lube your fired cases and run them into the NS die like it's an FL die. OR contact Redding, and possibly send them three of your fired cases and have them open up your NS die to reduce contact of the case body with the die. They could likely do the same with your FL die so that it sizes cases to fit the rifle's chamber.

I've found that most new brass is undersized too. The shoulder being moved 7 thou forward isn't a cause for concern unless you push it back to where it was in the new cases. A shoulder bump of 0.002-0.003 inch is enough for a field rifle.
 
Thanks. :)

In future I'll lube the neck and case body when neck sizing.
 
Just to set something straight about headspace.....

There are three common "standards" used to describe headspace, which is generally gauged. The gauging method is a quick and easy way to establish fit/no-fit for a system. Basically gauging sets up a Pass/Fail parameter as opposed to actually measuring anything. In a perfect world SAAMI spec'd gauges should all be mfgd to be within a thou of each other across the Fruited Plain..The gauging standards array themselves thusly:

-#1, Go Gauge.... set to be .002 over MIN SAAMI. Anything from .000 to .002 is "Go Gauge" spec. PASS

-#2, No-Go Gauge..... set to be from .003-.005. FAIL for civilian work. PASS for military usage.

-#3, Field Gauge.... set to be from .005-.006. FAIL for civilian, PASS for Battlefield Conditions. This is a gauge used only by military armorers for field expediency when weapons are being graded for battle work.


What this means is that when you're talking about chambers .007 or maybe even .010 over unfired brass, YOU'VE GOT A SEVERE HEADSPACE PROBLEM! Pisces, you need to be more specific. I strongly DOUBT that a gun left the factory with ten thou headspace! Would you please elaborate as to how you've arrived at these figures? (((( THIS sentence is unclear to me... "The case length remains about the same after the first firing and is about 10 thou less than the max chamber length."...... What do you mean "ten thou less than max?")))

And where your brass came from? Are these untouched factory cases? When you're up in even the .007 range I've got to disagree with Larry a little, you absolutely COULD experience a first-firing casehead separation with .007-.010 headspace......

Here's the deal...... shoulders DO NOT "move forward" EVER without you've got a false shoulder, an extractor or a belt holding the case in place. A bullet "seated long" WILL NOT DO IT!! This Old Wive's Tale needs to DIE!!

Shoulders can only move further BACK, it's the base of the case that stretches to make the cartridge longer. KNOW this and understand that if you're stretching your cases this far THEY WILL COME APART.

Now, after you've got properly fireformed cases then maintaining them is a matter of gently bumping the shoulders back a thou or less each firing. Going further like .002-.003 will cause "necks to grow" which simply IS the road to casehead separation. Necks don't "grow"!!! Bases stretch and you shove the excess neck brass up through the sizer when you resize. IF your OAL is increasing during your loading/shooting cycle then your dies are adjusted wrong. You must fix the problem or you need to throw your cases away after 3-4 reloadings.

please explain more about the ".007" and ".010" measurements......

thanks

al
 
Thanks for the information. I'll try and explain what I'm doing.

The 10 thou referred to is the difference between the fired case length and the chamber length - as measured with a home made tool.

The + 7 thou comes from measuring the case (new factory brass from Midway UK) before and after firing using a home made collar, that fits over the neck of the case, and is bevelled on the inside face to approximately match the shoulder angle.

I read somewhere that one indicator of excessive headspace is primers being pushed back out of their pockets. This is not happening. :confused:
 
pisces said:
Thanks for the information. I'll try and explain what I'm doing.

The 10 thou referred to is the difference between the fired case length and the chamber length - as measured with a home made tool.

The + 7 thou comes from measuring the case (new factory brass from Midway UK) before and after firing using a home made collar, that fits over the neck of the case, and is bevelled on the inside face to approximately match the shoulder angle.

I read somewhere that one indicator of excessive headspace is primers being pushed back out of their pockets. This is not happening. :confused:
Click to expand...

By "chamber length" do you mean to the shoulder? SAME measurement as the .007 measurement?

For the .007 measurement we don't really have a baseline sooooooo, can you do me a favor. Let's check the headspace using cartridge cases. pick out several random cases and put a layer of masking tape on the head, over the lettering. Trim off the excess with a razor and try in the chamber. Add another layer and try again. When you encounter refusal on your cases then carefully peel off the tape and measure the thickness of the trimmed masking tape "shim." This will give you another headspace datum.... compare this with your measurements.

The popped up primer indicator is only relevant if your loads are running at a low enough pressure that the brass DOES NOT STRETCH...... "starting loads" and such, in the range of 45.000 CUP, will exhibit this. If your primers are not popped up then you've either got NO excess headspace or your pressures are such that the cases are stretching back to slam the boltface. An indication should be prematurely flattened primers, primers ironed clear across the primer pocket hole, flattened to the edges. In fact, such primers will sometimes be "mushroomed" or rolled over wider around the rim.

keep us posted, let's get it figgered eh!

al
 
Probably my terminology isn't right. :eek: By chamber length I mean the distance between the start of the reamed section, at the bolt face, to the very end of the reamed section for the neck.

I have just tried your idea using some masking tape on new cases and found I can add 7 to 8 thou of tape before the bolt refuses to close.

I used my .17 Rem Fireball Possum Creek case trimmer (after removing the inner cutting section) as a spacer and measured the case length increase (case head to shoulder) for new and fired cases. This technique also gave me a 7 thou increase - the same as I had with my home made tool.

I'm running fairly low charges, 3,500 fps from 17.7 grains of H322 with a 25 grain Hornady HP. Quickload predicts a 45 K psi chamber pressure. Whereas 55 K psi is, I believe, max chamber pressure. So, not hot loads.

As this is a new gun, I contacted the gunsmith at the Remington importer today and he reckons I should send the rifle back so that they can measure the headspace using Go/No-Go gauges.

What do you think ?
 
Here is some deminsions for you.

17 rem fireball

Parent case .221 Remington Fireball
Bullet diameter .172 in (4.4 mm)
Neck diameter .206 in (5.2 mm)
Shoulder diameter .3673 in (9.33 mm)
Base diameter .3769 in (9.57 mm)
Case length 1.420 in (36.1 mm)
Primer type Small Rifle


Hovis
 
The headspace on the .222 Rem family of cases is measured at a datum point on the shoulder of the case or chamber that's 0.330" in diameter. Any other measurement point will give a faulty/false measurement.

The measurement of cases can be done with a collar with an UNBEVELLED edge that's 0.330" in ID.

Al, I'm afraid I've got to disagree with you on the danger of excessive headspace. Too much headspace will shorten case life, but unless pressures are astronomical a case failure is unlikely. Bob Greenleaf had an article in Precision Shooting a few years back about experiments done at Savage when he was an engineer there. They adjusted chamber headspace until the firing pin could not fire the primer, adjusted the firing pin to get it to reach and fire the primer, but no catastrophic case failures were experienced. The main problem with excessive headspace is seriously shortened case life IF the case shoulder is pushed back to its original position. Several years back I watched a young guy firing reloads in a Krag. Every round he'd have to extract the fired case body out of the chamber because the heads were separating from the rest of the case completely or partially. He'd FL sized the cases back to their original dimensions, pushing the shoulder back 1/8" or more from eyeballing a fired and unfired round. The cases had all been fired in his rifle once before.

In rifles like the Krag and SMLE that were chambered for rimmed cases the chambers were cut very "generously". If pressures are held to standard, and cases either neck sized or FL sized in a custom die cut to match the rifle's chamber case life is good. I had an old Ruger 77 in .22-250 that had a chamber that was WAY oversized in diameter. If those cases were FL sized after every firing, case life was 3 or 4 firings at moderate pressures before incipient head separations occurred. If they were neck sized they'd last 10 or so firings before the cases went south.
 
Larry Elliott said:
Al, I'm afraid I've got to disagree with you on the danger of excessive headspace. Too much headspace will shorten case life, but unless pressures are astronomical a case failure is unlikely. Bob Greenleaf had an article in Precision Shooting a few years back about experiments done at Savage when he was an engineer there. They adjusted chamber headspace until the firing pin could not fire the primer, adjusted the firing pin to get it to reach and fire the primer, but no catastrophic case failures were experienced. The main problem with excessive headspace is seriously shortened case life IF the case shoulder is pushed back to its original position. Several years back I watched a young guy firing reloads in a Krag. Every round he'd have to extract the fired case body out of the chamber because the heads were separating from the rest of the case completely or partially.
Click to expand...

I'll agree with this...... You really shouldn't experience a separation on the first firing even with excessive headspace. NEW brass and ONE firing in the oversized chamber and it's doubtful that caseheads will break off. But it's imperative that you then maintain the case using minimal shoulder setback.


Pisces.....

Were it me and were I keeping he rifle I'd form a false shoulder on the cases and fireform them correctly (I actually DO do this with several rifle which have excess headspace) But Larry's right, no real danger involved in firing once with the excess. Based on every thing I've heard the rifle does have a over-long chamber. The factory will replace the barrel if you can measure .007-.008 headspace.

Your call I guess. If it shoots good I'd count that as a blessing, burn that barrel up and then move on to a custom tube....

al
 
Larry Elliott said:
The headspace on the .222 Rem family of cases is measured at a datum point on the shoulder of the case or chamber that's 0.330" in diameter. Any other measurement point will give a faulty/false measurement.

The measurement of cases can be done with a collar with an UNBEVELLED edge that's 0.330" in ID.
Click to expand...

Thanks for that gem of info'. :)

It's taken me a couple of days to make an exact tool to these dimensions. But now, the result is that the headspace, as measured by the difference in case face to shoulder length on fired/unfired cases, drops from 7 thou' to zero. :)

Returning to my original query I'll just lube the case body slightly to ease the interference fit of a fired case in the neck sizing die.

Thanks for all the replies. :)
 
Do your fired cases have a noticeable bulge right above the extractor groove, ~0.2" above the head of the case? This could indicate a chamber that's too large in diameter at the body. I've seen this on cases fired in factory rifles, and sometimes it's quite pronounced. If it's bad the bulge can be seen and felt without a lot of effort.

That could be the problem here, but since manufacturers always warn us to "only use new factory ammunition from a reliable source" I'm sure that there response wouldn't be of any help. "So the heads fall off cases after only three or four (re)loadings, you really ought to go tell someone who cares." :eek:
 
No noticeable bulge.

The case diameter is 0.373" at the extractor groove; 0.374" when measured 0.2" from the case head; 0.372" midway along the body; 0.366" at the shoulder.

In UK, I've been told by the importer that the rifle is not covered by the Remington warranty if the user is reloading.
 
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You might have a die that was cut a tad undersized then. Redding makes a good die, but anyone can have an off day.
 
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