Chamber too short??

[coldboreshot]

There are lots of different 223 chambers. Before you modify it in any way, ask what reamer they used. They will fix it if it is not right.

I agree to a certain extent. I am not aware of any SAAMI spec reamer or any custom reamer made with zero throat length.

 

[Paddyd]

Just got off the phone with Criterion . They're going to send me a return label and want to inspect the barrel.

 

[Coyotefurharvester]

From the drawning I get 1.7720 to 1.787 case length. 1.8570 - 1.812 = 0.045 throat. Total length + 0.015".

 

[Ray Gross]

Freebore length.View attachment 1131581

Be careful using this chart. The C diameters are incorrect.

The C diameters listed on the chart are most likely taken at the breech face (or at the left limit of K, on the chart).

SAAMI, which is already generous, specs the 'C' diameter at .3769. Reamer makers generally call this diameter, taken at a point .200 forward of the Breach face, the 'Base diameter'. Which is confusing.

If you look at the SAAMI 223 Rem Print and compare it to the C diameters listed on the chart, most of them closely correspond to the SAAMI breach diameter of .3804.

In other words, if you spec a base diameter from this chart, you will have a very big diameter chamber. Especially considering SAAMI MAX Cartridge diameter at this point is .3759 and Lapua brass is about .374

 

[243winxb]

What is the normal freebore in a "standard" 223R chambe

A good question for a gunsmith. Not I.

SAAMI - looks like 1.812" Then tapers from .224" diameter to 1.857"

Freebore .025" SAAMI ?

But may be different depending on what reamer was used, .223 or 5.56. As in reamer chart posted.

 

[243winxb]

confusing

Yes it is. The SAAMI drawing has

Chamber. Unless otherwise noted. All dia. + .002" [0.05]

 

[K22]

The first bullet I tried was a 55g Nosler FBHP ( Midway Dogtown) loaded out to 2.260 per the Nosler book. When chambered, it pushed that bullet back into the case till the ogive was actually below the case mouth.. Something aint right with this one and I'm not shooting it till I get it inspected by a good smith. I ordered this barrel with the 9 twist with the explicit instruction to be able to shoot up to a 70 gn bullet. If I only wanted to shoot a 50 to 55 I'd have ordered a 12 twist.

Agree - something isn't right. Good idea - don't shoot it until this issue is resolved satisfactorily.

 

[tommeboy]

Your going to get it back and the bullet is going to be falling out of the case.

 

[Paddyd]

Your going to get it back and the bullet is going to be falling out of the case.

??? How so? Chamber dimensions in the barrel have nothing to do with how much neck tension my sizing die puts on the case. Regardless of the rifle loading for, my die sizes the inside of the case neck at .222" dia.

 

[tommeboy]

They are going to lengthen the throat to make you happy but it will be so long the bullets will probably fall out.

 

[Paddyd]

They are going to lengthen the throat to make you happy but it will be so long the bullets will probably fall out.

I find that doubtful

 

[243winxb]

prefit barrel

A custom barrel can be chambered to a dummy rounds COL that you supply.

 

[tclaunch]

This has the looks of total lack of communication between the parties. Let them know how much freebore you want or include a dummy round with your bullet seated to where you want it in a dummy 223 case. This could have been very easily avoided.

The topic of this thread is "chamber to short" and is not the case if you can close the bolt on a piece of brass. It will be confusing to use this in discussions on how to resolve the "freebore is to short".

 

[Paddyd]

Not to nitpick ,BUT, I think since it is cut with the same "chambering" reamer, freebore is in fact an integral part of the chamber... So, if there is insufficient freebore to chamber a Nosler 55gn FBHP to the length specified in the bullet manufacturers loading manual (2.260") without the lands pushing the bullet back into the case to an OAL of 2.145" jammed, then in my humble opinion, my chamber is indeed too short. I could be wrong, but I will find out soon enough. UPS delivered it to the maker yesterday AM.

 

[NorCalMikie]

And REMEMBER, if you go long, you CAN'T go back!!
If you go short, you CAN go longer. And the throat WILL wear. Probably sooner than you expect.

 

[Paddyd]

And REMEMBER, if you go long, you CAN'T go back!!
If you go short, you CAN go longer. And the throat WILL wear. Probably sooner than you expect.

I agree. I sent it back with no instructions for any modifications. I called them up when I realized that virtually none of the bullets I had with the exception of Hornady FMJ 55's would chamber when seated to the book recommended lengths without being fully jammed in the lands so far it was also pushing the bullets back into the case. I verified it all with a Hornady modified case too. As soon as I described what I was seeing they asked me to return it for a full inspection. I will confer with them as to whether it is me being full of shit or if in fact there is something up with it. For me it is better safe now than sorry later.
My Model 70 HV 223 is the standard 223 chambering and I have to seat longer than the book to get to the lands. This one is just the opposite.

 

[chuckshooter]

I like this definition from wikipedia

The chamber is the rearmost portion of a firearm barrel that has been formed to accept a specific cartridge or shell. For firearms having a rifled barrel, the bullet typically extends forward from the leading edge of the cartridge. The portion of the barrel forward of the chamber that provides clearance for the loaded bullet of a cartridge is known as the throat. The throat is composed of both a freebore and a leade.

also there are still gunsmiths that chamber with a chambering reamer and then cut the throat with a throating reamer.
I did eventually understand what you were trying to say, but it would have been more easily understood if you had said that you think your throat wasn't cut deep enough. like you said, I'm not trying to nitpik, just to inform. lets just see what CBI has to say.

 

[tommeboy]

 

[NorCalMikie]

I will confer with them as to whether it is me being full of shit or if in fact there is something up with it.

Not full of shit but more not being sure about what you've got. IMHO, forget the length listed in the book. Probably designed more to "mag length" than anything else. Any longer than listed won't fit the mag. You'll be building custom loads to fit YOUR rig. AND, long throat and shorter bullets CAN have the bullets falling out of the neck if you're trying to reach the lands.
If it was me, I would have been building loads with LOTS of jump to the lands and let the target tell me in I was on the right track. Never had a target lie to me. And you may have been surprised at the accuracy you could have come up with. Now, you'll have to wait and see what results you get when the barrel is returned. Slow down, back up and take one step at a time. My guess is MOST of us have been there and pretty much gone thru the same thing. Takes time to build experience.

 

[Ray Gross]

...[snip]...I ordered this barrel with the 9 twist with the explicit instruction to be able to shoot up to a 70 gn bullet. If I only wanted to shoot a 50 to 55 I'd have ordered a 12 twist.

Different bullets in the same weight class, loaded to the exact same COAL, can have very different relationships to the lands. A long ogive bullet will be farther from intercepting the lands than shorter ogive bullet of the same weight loaded to the same COAL.

The type of ogive will also affect the relationship.

One bullet may be seated 80% into the neck and still be mag length and only jumping .010 to the lands, while another has to be seated much deeper, to get the same bullet jump (and may be still too long for feeding from a mag).

This may be your situation.

It is possible that for some, maybe even most, 70+/- gr bullets, the throat that you have is entirely appropriate as is.

We often deal with this situation and ultimately have to ask the customer to pick a specific bullet, so that we can set the throat properly.