7PRC Partition wont chamber

[mtnbound]

Update. Got home this evening after borrowing a few 7mm bullets from a friend.
I loaded 162 gn Hornady sst @ 3.337 - wouldn’t chamber
I loaded 150 gn sierra matchking at 3.268- wouldn’t chamber
I loaded 140 gn Barnes ttsx - wouldn’t chamber
I loaded a 185 Nosler rdf at 3.439- wouldn’t chamber.

So then I decided to reload all these at their book length from their manufacturers book data.

So I loaded 162 Hornady sst at 3.070,
I loaded a 150 gn match king at 3.100
I loaded a 140gn Barnes ttsx at 3.110
And I loaded a 185 Nosler rdf at 3.320

I can get these to chamber if I force them. The rdf was so rough that it seated the bullet to 3.317.

Most importantly I’m noticing to chamber any of these bullets even a lil shorter than book length in order to get them to chamber when the bolt should rotate I’m having to force the bolt further I’m assuming jamming the bullets into the lands and I can feel the extractor snap over the case rim and then the bolt will rotate down. I have other tikkas and I went grab all of them and none of them have this phenomenon. Or feeling. What say you?

Something is messed up with the barrels' chamber. When you talked with the GS, did you ask him about the 2 spent shells and what load he tested your system with?

 

[Judd]

It could be your tooling and nothing to do with the chamber...I've got three different comparators and they will give me different answers. Meaning they are not interchangeable.

Don't call the gunsmith, yet...load the bullets for your chamber. It doesn't matter what the book says, it matters what the barrel or paper target tell you.

The short answer...we gave you above...keep pushing the bullet down in the case. Don't pay attention to the book or what it's telling you. Let the gun speak and it's telling you, your bullets are still seated too long. Then evaluate...one thing I'd be curious about...what marks are on the bullet? I bet you can see your lands engaging the bullet. How much is there?

 

[streamerfish]

It could be your tooling and nothing to do with the chamber...I've got three different comparators and they will give me different answers. Meaning they are not interchangeable.

Don't call the gunsmith, yet...load the bullets for your chamber. It doesn't matter what the book says, it matters what the barrel or paper target tell you.

The short answer...we gave you above...keep pushing the bullet down in the case. Don't pay attention to the book or what it's telling you. Let the gun speak and it's telling you, your bullets are still seated too long. Then evaluate...one thing I'd be curious about...what marks are on the bullet? I bet you can see your lands engaging the bullet. How much is there?

The bullets are seating too long because his chamber is too short. You shouldn't have to drop your OAL to well under saami specs to get it to fit. Especially in a modern chambering like a 7PRC.

 

[Judd]

The bullets are seating too long because his chamber is too short. You shouldn't have to drop your OAL to well under saami specs to get it to fit. Especially in a modern chambering like a 7PRC.

Not necessarily...the spec was based upon a 180 eldm...it has a LONG nose and high BC and it's an OAL number not a BTO number. He's not used a bullet with that long of a nose yet. You maybe right but the point is still the same...it doesn't matter and it will still shoot with a short freebore, seat the bullet further in the case and see how it sets up.

 

[LaHunter]

Update. Got home this evening after borrowing a few 7mm bullets from a friend.
I loaded 162 gn Hornady sst @ 3.337 - wouldn’t chamber
I loaded 150 gn sierra matchking at 3.268- wouldn’t chamber
I loaded 140 gn Barnes ttsx - wouldn’t chamber
I loaded a 185 Nosler rdf at 3.439- wouldn’t chamber.

So then I decided to reload all these at their book length from their manufacturers book data.

So I loaded 162 Hornady sst at 3.070,
I loaded a 150 gn match king at 3.100
I loaded a 140gn Barnes ttsx at 3.110
And I loaded a 185 Nosler rdf at 3.320

I can get these to chamber if I force them. The rdf was so rough that it seated the bullet to 3.317.

Most importantly I’m noticing to chamber any of these bullets even a lil shorter than book length in order to get them to chamber when the bolt should rotate I’m having to force the bolt further I’m assuming jamming the bullets into the lands and I can feel the extractor snap over the case rim and then the bolt will rotate down. I have other tikkas and I went grab all of them and none of them have this phenomenon. Or feeling. What say you?

You may have an extractor issue. I notice in your earlier posts that after attempting to close the bolt without success, you are able to pull the bolt to the rear and the cartridge is still not held by the extractor. The extractor should grab the cartridge without a lot of force. If your cartridge is not getting position in the bolt properly due to extractor being in the way, that would be causing your issue

 

[V00D00]

It could be your tooling and nothing to do with the chamber...I've got three different comparators and they will give me different answers. Meaning they are not interchangeable.

Don't call the gunsmith, yet...load the bullets for your chamber. It doesn't matter what the book says, it matters what the barrel or paper target tell you.

The short answer...we gave you above...keep pushing the bullet down in the case. Don't pay attention to the book or what it's telling you. Let the gun speak and it's telling you, your bullets are still seated too long. Then evaluate...one thing I'd be curious about...what marks are on the bullet? I bet you can see your lands engaging the bullet. How much is there?

this is the smiths advice as well. find the lands, load 50 tho off and see what it does on paper and we'll go from there. then he proceeded with make sure the barrel is clear and send it. its either gonna go or its gonna blow lol

 

[wapitibob]

I just measured a 140 TSX in my 7prc using a comparator and got 3.230" oal.
A 140 TTSX at 3.275" oal.

 

[V00D00]

I just measured a 140 TSX in my 7prc using a comparator and got 3.230" oal.
A 140 TTSX at 3.275" oal.

i loaded a 140 gn barnes ttsx bt @ 3.110 per barne's load data and when i slid the bolt forward i couldnt turn the bolt handle without first pushing the bolt toward the muzzle untili felt the extractor jump over the case mouth then once it clicked i was able to turn the handle.

 

[streamerfish]

Not necessarily...the spec was based upon a 180 eldm...it has a LONG nose and high BC and it's an OAL number not a BTO number. He's not used a bullet with that long of a nose yet. You maybe right but the point is still the same...it doesn't matter and it will still shoot with a short freebore, seat the bullet further in the case and see how it sets up.

I get your point.....

But the OP said that he communicated that he hunts with a 175 partition, then messes around with more target style bullets in the summer.

It would make no sense to ream a chamber around a ELDM when the main purpose is to hunt with a 175gr partition.

Its pretty easy to just ream it to standard, then your partition will work at a standard length that it should be at. And you can play around with the ELDM or RDF or whatever, probably load them a bit longer in the same chamber and have your summer target shooting.

Maybe it was some kind of miscommunication or understanding....And maybe I'm not understanding also...But it seems that I would want it setup to shoot a 175 partition at 3.25/3.26 OAL.

It just seems very backwards to me.

 

[wapitibob]

i loaded a 140 gn barnes ttsx bt @ 3.110 per barne's load data and when i slid the bolt forward i couldnt turn the bolt handle without first pushing the bolt toward the muzzle untili felt the extractor jump over the case mouth then once it clicked i was able to turn the handle.

I've never felt an extractor no matter where I loaded the bullet. If your extractor is hung up and not letting the case head get to the bolt face, that would easily cause your issue; the bolt lugs aren't forward enough to clear the action races. You're basically adding another .100 to the bolt face.

 

[streamerfish]

I've never felt an extractor no matter where I loaded the bullet. If your extractor is hung up and not letting the case head get to the bolt face, that would easily cause your issue.

Yeah, potentially there is something else going on here....

 

[V00D00]

I've never felt an extractor no matter where I loaded the bullet. If your extractor is hung up and not letting the case head get to the bolt face, that would easily cause your issue; the bolt lugs aren't forward enough to clear the action races. You're basically adding another .100 to the bolt face.

im assuming its because the case isnt in the chamber forward enough. i can literally push it forward when the bolt stops, feel the extractor jump over the case and hear it snap. ill video it.

 

[V00D00]

I've never felt an extractor no matter where I loaded the bullet. If your extractor is hung up and not letting the case head get to the bolt face, that would easily cause your issue; the bolt lugs aren't forward enough to clear the action races. You're basically adding another .100 to the bolt face.

 

[Judd]

I get your point.....

But the OP said that he communicated that he hunts with a 175 partition, then messes around with more target style bullets in the summer.

It would make no sense to ream a chamber around a ELDM when the main purpose is to hunt with a 175gr partition.

Its pretty easy to just ream it to standard, then your partition will work at a standard length that it should be at. And you can play around with the ELDM or RDF or whatever, probably load them a bit longer in the same chamber and have your summer target shooting.

Maybe it was some kind of miscommunication or understanding....And maybe I'm not understanding also...But it seems that I would want it setup to shoot a 175 partition at 3.25/3.26 OAL.

It just seems very backwards to me.

Most guys who build guns, not all but most...use saami spec'd reamers. The reason they do that is because it keeps the phone from ringing most of the time. That's always the goal...send the gun home and hope the phone doesn't ring later. Emails and texts of dead critters or another gun build started is all the post gun delivery communications guys want.

This is a new cartridge, saami'd in 2022, and it was introduced by wHornady, and the 180 eldm was used for the spec. The Partition was released in 1948 (I was wrong about throwing away 1960's technology, it's even worse than that ) and those long nosed bullets were definitely not a thing back then. You get a lot of that OAL in a part of the bullet that isn't touching the rifling. So the freebore will be shorter than say a chamber designed for a Partition.

I'd be willing to bet factory 180 eldm or 175 eldx ammo would chamber in his chamber with no problems at all.

I will put a small caveat on the prc saami chambers....they are tight on the back end and will create clickers if reloaded with stout charges, unless a reamer with a fatter .200 line reamer was used. Alex Wheeler came out with the solution due to his experience with clickers in the benchrest world...a lot of guys are using an "AW" chamber to remove that possibility. Any other change was minor in nature and that being the main reason for the revision. As a reloader, I prefer the AW chamber.

 

[V00D00]

Most guys who build guns, not all but most...use saami spec'd reamers. The reason they do that is because it keeps the phone from ringing most of the time. That's always the goal...send the gun home and hope the phone doesn't ring later. Emails and texts of dead critters or another gun build started is all the post gun delivery communications guys want.

This is a new cartridge, saami'd in 2022, and it was introduced by wHornady, and the 180 eldm was used for the spec. The Partition was released in 1948 (I was wrong about throwing away 1960's technology, it's even worse than that ) and those long nosed bullets were definitely not a thing back then. You get a lot of that OAL in a part of the bullet that isn't touching the rifling. So the freebore will be shorter than say a chamber designed for a Partition.

I'd be willing to bet factory 180 eldm or 175 eldx ammo would chamber in his chamber with no problems at all.

I will put a small caveat on the prc saami chambers....they are tight on the back end and will create clickers if reloaded with stout charges, unless a reamer with a fatter .200 line reamer was used. Alex Wheeler came out with the solution due to his experience with clickers in the benchrest world...a lot of guys are using an "AW" chamber to remove that possibility. Any other change was minor in nature and that being the main reason for the revision. As a reloader, I prefer the AW chamber.

I’m not doubting u. This is basically what’s he’s saying. And my bro n law is gonna bring over a factor eldx to see if it chambers. The smith said he shot it with stock eldx with no issues. And that he didn’t use any kind of custom reamer. He suggest I find the lands, load 50 tho off and see what happens with a bullet like eldm or eldx or Nosler rdf. I’ll give it a shot. I told him give me a week or so and if I’m still feeling like something’s weird I’ll send it for him to look at. I just didn’t want to ship a rifle across the country for him to say he doesn’t see anything wrong but will ream it if I want him to

 

[Smithb9841]

i loaded a 140 gn barnes ttsx bt @ 3.110 per barne's load data and when i slid the bolt forward i couldnt turn the bolt handle without first pushing the bolt toward the muzzle untili felt the extractor jump over the case mouth then once it clicked i was able to turn the handle.

Have you tried factory ammo to see how that chambers?

 

[V00D00]

Have you tried factory ammo to see how that chambers?

Not yet. I have to get some. Buddy gonna bring me a couple factory eldx Sunday

 

[streamerfish]

Most guys who build guns, not all but most...use saami spec'd reamers. The reason they do that is because it keeps the phone from ringing most of the time. That's always the goal...send the gun home and hope the phone doesn't ring later. Emails and texts of dead critters or another gun build started is all the post gun delivery communications guys want.

This is a new cartridge, saami'd in 2022, and it was introduced by wHornady, and the 180 eldm was used for the spec. The Partition was released in 1948 (I was wrong about throwing away 1960's technology, it's even worse than that ) and those long nosed bullets were definitely not a thing back then. You get a lot of that OAL in a part of the bullet that isn't touching the rifling. So the freebore will be shorter than say a chamber designed for a Partition.

I'd be willing to bet factory 180 eldm or 175 eldx ammo would chamber in his chamber with no problems at all.

I will put a small caveat on the prc saami chambers....they are tight on the back end and will create clickers if reloaded with stout charges, unless a reamer with a fatter .200 line reamer was used. Alex Wheeler came out with the solution due to his experience with clickers in the benchrest world...a lot of guys are using an "AW" chamber to remove that possibility. Any other change was minor in nature and that being the main reason for the revision. As a reloader, I prefer the AW chamber.

I could be wrong....But I would surmise that the partition load data that nosler provides for it should be viable. Hornady themselves has load data for the 175gr Interlock SP at 3.265 length. Length and shape wise that should be a pretty comparable bullet to the 175gr partition.

TO THE OP>
If that 185 RDF wouldn't fit at book 3.320 and it had to be forced to fit at 3.317....then that 180 ELDM is going to be very borderline to fit at 3.320 I would say.



I

 

[V00D00]

Update. On the way home I stopped bought a factory loaded box of eldx. Their coal was measured at 3.291 and Chambered perfectly. Sat down with a partition at the press and did get it to chamber smoothly, at 3.009 unfortunately

 

[wind gypsy]

Sounds like your throat might be a little under SAAMI spec but hard to say without first hand experience with those bullets in a PRC. I wouldn't be surprised at all if a partition is jammed at 0.300"+ shorter than a long nosed bullet with more aggressive profile. It would take an obscene amount of freebore to work with how that partition is seated in the OP.

Because berger publishes specs better than most here's an example: 150 Classic hunter has a nose length that is 0.300" shorter than a 195 EOL. I would guess that the partition nose is shorter than a 150 CH.

Edit to add: Think of it this way - nominal 7 PRC case neck length is 0.287". SAAMI freebore (Section in front of mouth that is 0.0006" larger diameter than nominal bullet diameter) is 0.233" long, at the end of which the leade angle starts tapering slowing to bore and groove dimensions. So if you look at the bearing surface sticking out of the case neck and it is as long or longer than the neck - expect to be in the lands.