Do I have a super short throat - .223 rem

[Sogan]

Completing two different land tests, I get a base to ogive measurement of 1.827 when using a 75 eld-m. I’m about 99% confident that the lands are within .001 of this measurement.

I’ve measured the following for base to ogive:
-CBC 77gr OTM at 1.867
-Fiochi 50gr Vmax at 1.839

Appears that everything is jammed with this chamber. Is my throat/chamber (whatever it’s called) super short for a “223 rem”. Terminus Zeus, hand tight barrel but I did torque it on to 65inch pounds.

 

[Doom]

It’s difficult to compare your measurements to others without knowing what tool (comparator) you use and even then it’s problematic. For the base to ogive measurement (75 eldm) you have, what is the corresponding overall length.

I’m confused about the other measurements, are they base to ogive of factory cartridges?

Has the barrel/action been headspaced? I’m confused by your last sentence.

 

[Steel head]

Yea
Comparators all vary.
An overall length is a better measurement to compare with others.

 

[Sogan]

The factory rounds are base to ogive as well. I take some COAL measurements tomorrow and add those to this post

 

[Sogan]

COAL lengths are as follows:
-Round that I used to find the start of the lands and have been basing my measurements and statements above off of has a base to ogive of 1.827 and has a COAL of 2.375
-CBC 77 gr COAL 2.247
-Fiochi 50gr vmax COAL 2.227

 

[Jabot]

I'm running the 75 grain hornady at a coal of 2.355,and a ctbo 1.937 it feeds great out of a mag with a velocity or 3020 fps . Under 1/2 moa group . Hope this helps

 

[Dstoenner]

Freebore of a 223 remington chamber is really short because it was spec’d for light bullets. A 556 is more like .080 which is long for a target chamber. The Wylde was a compromise.

What does your barrel say it was chambered to?

David

 

[Sogan]

Freebore of a 223 remington chamber is really short because it was spec’d for light bullets. A 556 is more like .080 which is long for a target chamber. The Wylde was a compromise.

What does your barrel say it was chambered to?

David

223 rem

 

[Dstoenner]

I looked up the freebore on a 223 Rem chamber in the SAAMI specs and it is .025. Pretty short

David

 

[Jabot]

This seams odd u have s 90 thousandths shorter cbto ,but u r 20 thousandths longer in oal. What r u using to measure cbto

COAL lengths are as follows:
-Round that I used to find the start of the lands and have been basing my measurements and statements above off of has a base to ogive of 1.827 and has a COAL of 2.375
-CBC 77 gr COAL 2.247
-Fiochi 50gr vmax COAL 2.227

 

[Sogan]

This seams odd u have s 90 thousandths shorter cbto ,but u r 20 thousandths longer in oal. What r u using to measure cbto

hornady bullet comparator

 

[918v]

You can’t transfer measurements from one bullet to another. A comparator only works on one bullet at a time. You use it to measure bto before and after die adjustment.

 

[Jabot]

Understood how the comparter works and that bullet measurements don't transfer from one to another. I just think it's odd his ctbo is so short compared to oal

 

[Sogan]

Understood how the comparter works and that bullet measurements don't transfer from one to another. I just think it's odd his ctbo is so short compared to oal

75 eldm are certainly long compared to 50gr vmax is my only thought on it. ALOT of the 75 eldm is in the case in my scenario because it’s loading super short, or at least I think it is, to not be jammed idk the lands based on my lands test

 

[Dstoenner]

75 eldm are certainly long compared to 50gr vmax is my only thought on it. ALOT of the 75 eldm is in the case in my scenario because it’s loading super short, or at least I think it is, to not be jammed idk the lands based on my lands test

You cannot load a 75 ELD-M (Amax) at mag length. It wasn't meant for that. Shortest it can be loaded is 2.299 otherwise the front ogive is below the mouth of the case.

David

 

[918v]

Understood how the comparter works and that bullet measurements don't transfer from one to another. I just think it's odd his ctbo is so short compared to oal

you understand but he doesn’t

 

[Sogan]

you understand but he doesn’t

I used the exact same bullet that I found the lands on with the comparator. Then I took the same bullet and did a seating test until it was no longer getting caught on the lands (same test that Brian Allen from A-team teaches). Same bullet was used through two tests

 

[918v]

So you found the lands with the ELD at 1.827” and now you think that factory ammo will jam because the bto on it is longer than 1.827” ? Because that’s how your post reads.

 

[Sogan]

So you found the lands with the ELD at 1.827” and now you think that factory ammo will jam because the bto on it is longer than 1.827” ? Because that’s how your post reads.

That would be correct. Not all factory rounds have resistance loading but 1 out of 5 would certainly have a stiffer bolt on the down motion. Sure makes me think they are jamming with that.

I must be confused because I know that the COAL of a round doesn’t matter because only the ogive touches the lands and not the tip of the bullet. I thought that even different bullet types all have an ogive so if I measure BTO of the round and it was longer than where I think the lands are then even though it’s a different bullet it would still jam?

 

[Lunchbox27]

Have you reach out to the smith to ask his advice? I would start there. He would know the reamer used and what you could get with said projectiles.

 

[Sogan]

Have you reach out to the smith to ask his advice? I would start there. He would know the reamer used and what you could get with said projectiles.

I haven’t yet. I wanted to make sure I was on the right track first and had my ducks in a row

 

[918v]

That would be correct. Not all factory rounds have resistance loading but 1 out of 5 would certainly have a stiffer bolt on the down motion. Sure makes me think they are jamming with that.

I must be confused because I know that the COAL of a round doesn’t matter because only the ogive touches the lands and not the tip of the bullet. I thought that even different bullet types all have an ogive so if I measure BTO of the round and it was longer than where I think the lands are then even though it’s a different bullet it would still jam?

OK, here’s how your perception is wrong:

The CBTO from a Hornady ELDM will be different than the CBTO from a SMK or whatever. Different profile bullets interface with the rifling in different spots on their ogjives. Your comparator is not an accurate representation of your rifling.

If you feel your bolt close hard it is prolly due to headspace. The throat will mark up a bullet due to runout, or side pressure from the ejector on the case head, etc.

I will bet you that factory ammo is well off the rifling in your chamber.

 

[Sogan]

OK, here’s how your perception is wrong:

The CBTO from a Hornady ELDM will be different than the CBTO from a SMK or whatever. Different profile bullets interface with the rifling in different spots on their ogjives. Your comparator is not an accurate representation of your rifling.

If you feel your bolt close hard it is prolly due to headspace. The throat will mark up a bullet due to runout, or side pressure from the ejector on the case head, etc.

I will bet you that factory ammo is well off the rifling in your chamber.

That makes sense. I appreciate the explanation

 

[Jabot]

Measure the diameter of your comparter is probably smaller than the lands on your rifle this is why it's not an accurate measurement of your lands.