RELOADING: Headspace

[Carlos Hathcock]

I know I'm new at the reloading game but I've been reading up on sizing, headspace, "jump", etc. Got me to thinking about somethin I experienced earlier.

Since day 1 I've had to slam the bolt closed on my Ruger RPR. I just figured it was new and needed time to loosen up and break in. Then I thought about it some more. Wondered if the bullet was making contact with the lands.

Simple test. Load a live round (safety on and safe direction of course) and try to open the bolt unfired. What happened confirmed my suspicions. Bolt would not open and I had to use a rubber mallet to do so. What I found next was even scarier.

Looks like it not just touching the lands but being seated deep into them! I can see clear marks on the bullet and I measured .030 from the neck to about where the marks stop. Not .003, but .030 or just over 1/4".



I know the pic isn't the greatest but the best I could do with the phone and lighting.

I've heard some people / rifles like land contact. Others recommend various degrees of jump. Again, not an expert but I think this is wrong. Your thoughts?

 

[togmaster]

Is this a hand load or factory ammo? You may have an issue with the chamber.

 

[kev74]

Is there only one scuff like that or 5 or 6 of them?

Is it factory ammo or a reload. In either case, the bolt shouldn't be hard to open on an unfired case. A phone call to Ruger is in order... unless the rifle shoots really well. Then you might not want to mess with it.

Headspace is the distance between the shoulder and the bolt. Free-bore is the amount of bore without rifling. The scuff on the bullet would be a free bore issue. The hard opening bolt could be either or both. You should be able to get a rough idea of freebore by measuring with a caliper, or a skinny ruller, etc. You'll need headspace gauges to accurately check the headspace.

 

[DoD1776]

That camera quality is great!

 

[Carlos Hathcock]

6mm Creedmoor.
Hornady 108 ELD match.
Scuffs all around.
Pic is from a magnifier app. Free and works very well for close ups.
Working on buying modified rounds to work with the OAL gage. My homemade ones didnt work as I'd hoped.

 

[meketrefe]

Hornady 108 ELD match.
Scuffs all around.
Pic is from a magnifier app. Free and works very well for close ups.
Working on buying modified rounds to work with the OAL gage. My homemade ones didnt work as I'd hoped.

There are two separate things here.
One is headspace that you can measure with a sized case. Do not need gauges for anything.

Two is the max coal dictated by the freebore. That is how far you can go before you start jamming the bullet in the lands or
even offset the bullet or worse (open the bolt only to find out you pulled the bullet out)

First thing is to find out what the spec for the chamber is, or at least should be by design like
SAAMI chambers.

What round is that one? 243, 6x47 lapua?? I didn't see it mentioned here.

It is not uncommon, mass manufacturers making a mistake with chambers as they pull the reamers from a stack.
It doesn't mean that it is the wrong chamber but it means what the actual reamer should be for the given round and objective.

Like 223 for example, there are over 12 different reamers one could use from different makers. All have slight changes
and while compatible with many rounds some will not take certain match rounds.

makes sense?

 

[gun_slinger_boy]

There's a quick and dirty way of figuring out the max COAL before the bullet starts touching lands. You would take the case and split the neck so that a seated bullet won't retain tension. You then seat the bullet fairly shallow and then chamber the round. On a bolt action rifle this would be ideal since you can manipulate the bolt slowly. On an automatic it would be best just to insert round by hand and then guide the bolt onto the round by hand. This will give you the absolute max COAL before touching the lands. In your case it should show if indeed you have some kind of problem. And for the love of pete. You said you were putting live rounds in to test. Just make a dummy round for testing!

 

[meketrefe]

You said you were putting live rounds in to test. Just make a dummy round for testing!

Every new bullet shoudl have a dummy round with the max coal and/or ideal coal for replication and one have the bullet adapter gauge to measure
from the datum and not the tip. So one could virtually reproduce any round that is deemed to be accurate or to verify COAL.

In my match rounds I keep at least 2 dummies or more for every different bullet and rifle that is the max coal, the accurate load or any other variant
for the same reason. The mild accurate load might have a different coal from the hot accurate load like in case of hunting loads.

Also the process you described is pretty typical and quick way but there is no need to split the neck. Simple take a fired case and size about 1/8 of the neck only so one has to stop very short.
That will give enough tension to hold the bullet but not enough to avoid gently pushing the bullet. The smoke of a candle or even a sharpie will
levave a clear mark of how the bullet is engaging.
there are other methods but they require tools and/or sacrificing a case but otherwise not necessary.

What I am intrigued here is about the actual chamber @Carlos Hathcock has.

Everything starts with knowing the chamber IMO. ...regardless of what the barrel says outside.

 

[Acer-m14]

could be the case shoulder needs to be set back a bit more ..

when i was reloading 223 , some SP and some plastic tip type ..

i ran into the same .. dang bolt wouldn't close on the vmax type .. all good on the SP's

but 2 diff brass head stamps .. all the vmax type were in rem brass ..

1/4 turn down on the resizing die fixed it .. it was a brass problem

 

[Carlos Hathcock]

Sorry. Chambered in 6mm Creedmoor.

Wasn't able to scare up a ton but found some bits on accurateshooter forum.

I just measured my RPR's throat last night and found that Hornady's 108 ELD match ammo is jamming into the lands .16"!! (Not .016"). I checked it 3 times, because I thought for sure that Ruger and Hornady MUST HAVE teamed up and compared notes on dimensions, when developing the 6mm Creed. Do you think this is something that I should just load accordingly for, or should I send my rifle back to Ruger for a reaming?

The Ruger should be using the .183 SAAMI freebore and my custom Creedmoor uses that and the factory 108 ammo at about 2.800" is .020" off the lands. So if you are jamming the 108 ELD factory ammo .16" then that is a super short chamber. I would check with Ruger.

Still looking for more but it sounds like this is not a standalone incident.

 

[tony]

Not trying to be a smart ass but...

.003 = 3 thousandths.
.030 = 30 thousandths.
.300 = 300 thousandths.
.250 = 1/4" or 250 thousandths

I reread the post part about slamming the bolt closed. Umm... don't slam it closed... If you had to slam it closed with factory ammunition you may have a tight chamber and may want to send it back to the factory.

But let's assume it is good. If you can close the bolt easily on one of your resized cases (no bullet) that's good. If it is hard to close on a sized case (no bullet) you need to move the shoulder back IF you can.

On a side note for the above. I don't know what kind of extractor set up your rifle has but if you can slip the case rim under the extractor that will help by not having to do it when you load a case into chamber and close bolt possibly giving you a false feel as the extractor slips over the rim.

For this next exercise lets assume the cartridge case headspace is good and the bolt closed easily on your resized case.

Hard to tell from picture but it looks like a lot of bullet hanging out of the case. Place a bullet alongside the loaded round to show how much bullet is in the case. If the base of the bullet is not below big end of the the shoulder taper seat the bullet a little deeper in the case. I like to use a sharpie and keep seating bullet deeper about 1/4 turn of the seating stem screw at a time until the sharpie is NO LONGER being wiped off. (apply sharpie to a clean bullet every time, it wipes off with alcohol) If you can be slightly (.010" or .015") off the lands that is a good place to check accuracy from. Your rifle may like more or less distance but you'll know where the origin of the bore is...

If I confused or you have a question about what I typed here PM me.

 

[meketrefe]

Sorry. Chambered in 6mm Creedmoor.

Wasn't able to scare up a ton but found some bits on accurateshooter forum.

I just measured my RPR's throat last night and found that Hornady's 108 ELD match ammo is jamming into the lands .16"!! (Not .016"). I checked it 3 times, because I thought for sure that Ruger and Hornady MUST HAVE teamed up and compared notes on dimensions, when developing the 6mm Creed. Do you think this is something that I should just load accordingly for, or should I send my rifle back to Ruger for a reaming?

The Ruger should be using the .183 SAAMI freebore and my custom Creedmoor uses that and the factory 108 ammo at about 2.800" is .020" off the lands. So if you are jamming the 108 ELD factory ammo .16" then that is a super short chamber. I would check with Ruger.

Still looking for more but it sounds like this is not a standalone incident.

This seems correct if we assume Ruger used the right reamer like this PTG reamer below that is 183 to 199 if you consider
the full tolerance. So the hornady should work w/o problems.

So it looks that the reamer they used is not the same intended for the hornady ammunition, or they made a mistake
that is not unusual with mass produced commercial rifles. I read of these mistakes with the RPR and even worse like
run out and those things. The good news you could fix that easily with a throater but probably better leave it to a gun
smith to tailor the chamber to the hornady factory ammo if that is what you are going to use. And while at it head-space it to it
at the same time, but one can do that with the barrel nut given if you have some basic tools and knowledge.

But I am afraid your chamber needs to be revisited. Ask Ruger and see what they have to say. ..sorry brother.

 

[Carlos Hathcock]

Not trying to be a smart ass but...

.003 = 3 thousandths.
.030 = 30 thousandths.
.300 = 300 thousandths.
.250 = 1/4" or 250 thousandths

I reread the post part about slamming the bolt closed. Umm... don't slam it closed... If you had to slam it closed with factory ammunition you may have a tight chamber and may want to send it back to the factory.

But let's assume it is good. If you can close the bolt easily on one of your resized cases (no bullet) that's good. If it is hard to close on a sized case (no bullet) you need to move the shoulder back IF you can.

On a side note for the above. I don't know what kind of extractor set up your rifle has but if you can slip the case rim under the extractor that will help by not having to do it when you load a case into chamber and close bolt possibly giving you a false feel as the extractor slips over the rim.

For this next exercise lets assume the cartridge case headspace is good and the bolt closed easily on your resized case.

Hard to tell from picture but it looks like a lot of bullet hanging out of the case. Place a bullet alongside the loaded round to show how much bullet is in the case. If the base of the bullet is not below big end of the the shoulder taper seat the bullet a little deeper in the case. I like to use a sharpie and keep seating bullet deeper about 1/4 turn of the seating stem screw at a time until the sharpie is NO LONGER being wiped off. (apply sharpie to a clean bullet every time, it wipes off with alcohol) If you can be slightly (.010" or .015") off the lands that is a good place to check accuracy from. Your rifle may like more or less distance but you'll know where the origin of the bore is...

If I confused or you have a question about what I typed here PM me.

Just want to be clear here. I've not made / fired reloads in this gun. All one brand Hornady factory ammo out of the box.

 

[tony]

Just want to be clear here. I've not made / fired reloads in this gun. All one brand Hornady factory ammo out of the box.

Factory ammunition only thus far. Got it!

Houston, we've got a problem...

Looks like a call to Ruger and Hornady would be pertinent at this time.

 

[meketrefe]

Just want to be clear here. I've not made / fired reloads in this gun. All one brand Hornady factory ammo out of the box.

Like I said, most likely yo have to call Ruger first.

If you want to make sure can you pull out a bullet or do you have a 108gr ELD bullet around?
take a flat surface like a piece of glass or old dvd. paint a 1" inch with a sharpie and while is fresh role the bullet there flat.
The marked area is going to be the bearing surface of that bullet. measure from hornady round how much it sticks out past
the neck and if the remaining bearing sourface is any longer than 183 to 199 thous. then call hornady but if it is less than that then
call Ruger. Whoever you call ask what is the precise / spec chamber they made the chamber or ammo for. Get the valid
reamer/reamers with the brand (like ptg above) in case you need to pass that to either manufacturer.

My bet is Ruger made the mistake since in the pictures it looks the rifling marks go deep into bullet.
Hard to say w/o measuring but it seems the PTG reamer above should be the right one for the hornady ammo you got.
Bottom line you have to know your chamber regardless of what it says outside the barrel with commercial rifles.

This happens all the time with popular well established rounds so imagine with odd or specialty rounds.

It is like 223, there are at least 12 different reamers any maker could use in a given time all compatible for
many rounds but will not work with certain others like the now obsolete 223 SAAMI itself. Nobody uses that anymore
in favor for a 5.56 or a hybrid match or wylde chamber. Less liabilities too.

 

[Carlos Hathcock]

Thanks for all your input. I'll be getting in touch with Ruger this week to see what their take is going to be on this. Stay tuned....

 

[Carlos Hathcock]

Better pics....

 

[meketrefe]

That's crazy. Call Ruger.

 

[Acer-m14]

Just my normal thinking process on things @meketrefe from the photos above with the marks so close to the case neck , wouldn't this show up on the other
ammo he uses ?? ..

 

[meketrefe]

Just my normal thinking process on things @meketrefe from the photos above with the marks so close to the case neck , wouldn't this show up on the other
ammo he uses ?? ..

hi Acer,

not necessarily.

Other ammo might not use even half of the free bore and therore there will be a long jump into the lands
but that is ok for hunting and other purposes. Even a longer round but with a VLD bullet that has a tangent ogive might
not have so much bearing surface and a more aggresive angle with a straight profile (tangent) so
might engage w/o problems. that is why VLD bullets with tangent ogive are more succettilbe to jump
and people tend to move them forward to stick them pretty close to the lands.

Hornady uses a now popular hybrid ogive profile and they make the ammo for this chamber that has a substantial
free bore, at least going by the PTG reamer blueprint I posted above.

We didn't get the precise measures from @Carlos Hathcock but it seems to me the chambering job
from ruger doesn't allow for much of the bearing surface to sit in the free-bore judging by how close the
rifling marks are from the mouth of the case.

Therefore I don't think is a small thing and even smaller bullets and tanget ogives might give problems.

That,... or the ammo is out of spec from factory, or there are more than one version of the same chamber,
but we cannot know w/o the measures.

The method above of pulling a bullet or using a new one that is the same will tell us how much of
the bearing surface is out of the case. The bearing surface out of the case might not be longer
than the freebore or for sure it will not chamber properly. At the same time, if we use that much
freebore and the bearing surface is still smaller but yet the angle of ogive is smaller than the angle of the
lands the bullet will touch some point further (different angles) , and specially hybrids because they are not
tangent after the freebore so one has to also account for the curve of that ogive.

sometimes is better to explain this with pictures or a whiteboard so folks can see but it ends up being a matter
of simple fitting of two objects, one being the chamber and the other the round.

We have two dimensions that are critical the base and shoulder (headspace) and the tip(bullet) and freebore that is MAX COAL for every different bullet in the market.

The headspace should be measured separately w/o any bullets at all. A piece of sized brass
might be all one needs.

Even if the headspace checks out one should inspect the chamber for obvious problems like
machine marks or a short tenon. Headspace might check out ok yet the chamber is not safe
to be fired. Not frequent but I have seen this before. Last time from a PSA AR15 barrel
with a short tenon where head-space was ok but it was fvcking dangerous as the rounds would
buldge like crazy. Of course the person who put together that Saturday Night Fever "El cheapo
PSA parts Special" AR didn't have a clue about how this would be possible. I had to explain with pen and paper.
I have seen other rugers and mossbergs with chambering proglems before but not a short tenon.
I also saw a model 1 barrel with a loose barrel extension.

Lots of crazy chit out there.

Ruger they are getting better every day but still crap out once in a while.

Lets see what carlos says.

 

[Carlos Hathcock]

Sorry. Tonight was a disaster. Hoping to get the numbers tomorrow after work.

 

[Carlos Hathcock]

So heres the verdict.

Measured COAL: 2.635
Factory Ammo COAL: 2.791-2.796






So, with my limited intelligence / knowledge I'd say the throat is wrong....real wrong. What say you?

 

[meketrefe]

Yes. one doesn't have to be einstein to see that with those pictures even if you didn't provide the rough measures. (thanks for that)
It is a huge difference.
These modern cartriges made after the BR and 6.5x47 lapua they follow the same directives.
They have lots of freebore for the use of match bullets and maximize case space.

So, yeah. call Ruger. they fucked up. no question about that.

sorry brother.

 

[Carlos Hathcock]

Yes. one doesn't have to be einstein to see that with those pictures even if you didn't provide the rough measures. (thanks for that)
It is a huge difference.
These modern cartriges made after the BR and 6.5x47 lapua they follow the same directives.
They have lots of freebore for the use of match bullets and maximize case space.

So, yeah. call Ruger. they fucked up. no question about that.

sorry brother.

As I suspected...and as is my luck.

 

[gun_slinger_boy]

Wow. Just wow.

 

[Carlos Hathcock]

So I emailed Ruger with a detailed description of what I found, and attached photos of the seated round proving the shallow throat, if one even exists at all. I asked some simple questions as I wanted to know what they would be planning to do to rectify the situation and what depth throat they would cut it to. Long and short of their response...give us a call and they'll get it back here to correct it. I may go out of pocket to take it to a Smith so I can work with someone who actually gives a shit.

 

[meketrefe]

So I emailed Ruger with a detailed description of what I found, and attached photos of the seated round proving the shallow throat, if one even exists at all. I asked some simple questions as I wanted to know what they would be planning to do to rectify the situation and what depth throat they would cut it to. Long and short of their response...give us a call and they'll get it back here to correct it. I may go out of pocket to take it to a Smith so I can work with someone who actually gives a shit.

humm... sorry to hear.

The thing with mass produced rifles is that when you get into the odd /specialty calibers their fast lane / mass production employees might not
be so familiar with the reamers and if there is a two step process like 2 reamers they might make mistakes even when instructions are clear.

It has been my observation that when it comes to this type of budget target rifles, Savage is the only one who delivers consistently, including
some of the not so frequent chamberings. Their mass produced barrels and chambers are so good that they are sold to other brands but not ruger.
Savage LRP model is probably the best value for comparable money and a better action and stock IMO. Not sure about the 6 creed though.
The ruger seems like a decent modern rifle and Ruger is getting there but not w/o the ocassional problems.

My honest advice is to actually take the rifle to a precission builder and have it all squared and lapped and the chamber with zero tolerances
to SAAMI spec and then you will be happier.

But if you send it to them shouldn't you at least give a chance to make it right? I don't think they can make it worse, don't you think?

Or get a precut barrel and the barrel nut and wrench is as simple as pie to swap but I think the gunsmith is a good approach if you consider
squaring the action if there is a problem with another part. Something that is not needed with savage LRP but it is needed with other brands including
the R700 factory actions that need blueprinting to then be in the precision category. Or if you have a friend who is a machinist or something
they can take some measures on the face of the reciever, threads angle, etc...

The word precission is tossed around a lot for marketing but it starts with precission machining I am afraid.

sorry this is happening to you brother. Just give a thought to the GS to see what they say, you know cry once.

Where do you live? Are you close to the finger lakes? You have some good precission builders in the area.
I just have no clue if they work with this action because normally they work with the usual proven actions.
That is why I would just call to get more info and be ahead. And continue to poke ruger at the same time.

 

[Carlos Hathcock]

I'm going to have a gunsmith look at this first. I'm just outside Buffalo. Rugers response did not make me feel like they were showing much concern and I'd rather not get it back from them only to find they fixed it but fixed it "wrong" and start knowing the UPS guy on a first name basis. I'll see what the local fella says and update. Thanks.

 

[Carlos Hathcock]

Better photo from the gunsmith.

 

[meketrefe]

Any updates?