A peculiar problem

[wvbearhunter]

As most of you know I have been doing a lot of 308 Win loading lately. Well, I picked up some Sierra 180 grain TGKs to try out and ran into an issue.

They WILL NOT chamber. No matter how deep or long I seat them, no matter how hard or soft I crimp. Zilch

I tried both Alpha and Fed brass, no difference however, as soon as i pull the projectile, the brass chambers.

I measured them just to be sure and they are .308.

My only conclusion is that it is the shape of the projectile. See the pic of the 180 tgk compared to the 195 tmk.

 

[waspocrew]

That's a pretty interesting comparison - ogive is way up there on the 180. Do you have a comparator to measure?

 

[wvbearhunter]

That's a pretty interesting comparison - ogive is way up there on the 180. Do you have a comparator to measure?

Sadly no, have not needed one.....til now

 

[MagnumManiac]

Sadly no, have not needed one.....til now

Easiest fix is to slit a case neck with 2 cuts opposite each other, clean up the burrs and size it, then long seat a bullet and carefully chamber it several times measuring either OAL or BTO and use that measurement to work off.
It must be into the rifling at the length you are loading it.

Cheers.

 

[wvbearhunter]

I worked on seating depths last night and found that they will not chamber until the oal is 2.77"!!! Which puts way too much projectile inside the casing in my opinion. Long seating 308win is not an optionwith these apparently

.

 

[Shane Lindsey]

It is if you are set up for it. Do you have a short action box for only 2.8"?

 

[BRADMOTO]

Sierra's have been great with putting the contact point of the ogive far forward on a lot of their offerings which work great for semi auto/mag restricted guns. Lessons the jump. This isn't doing you any favors though as you have found.

The VLDs put the contact point of the ogive further back and allow more of the ogive to ride free inside the barrel, allowing longer COALs.

It's just simply bullet design and construction.

 

[wvbearhunter]

I discovered a few minutes ago that Sierra released 2 different versions of this projectile, #4680 and #4681.

Apparently #4680 (which I have ) is designed specifically for 300wm/300prc and #4681 is for 308 Win and 30-06.

When I ordered these this was not disclosed nor was it available without some "google-fu".

 

[MagnumManiac]

I discovered a few minutes ago that Sierra released 2 different versions of this projectile, #4680 and #4681.

Apparently #4680 (which I have ) is designed specifically for 300wm/300prc and #4681 is for 308 Win and 30-06.

When I ordered these this was not disclosed nor was it available without some "google-fu".

Unfortunately, this happens with many bullet brands out there.
I booked my annual buffalo hunt in Northern Australia and noticed I had less than 20 bullets left for my 375H&H and 375 Weatherby, so I ordered more online and waited for them to arrive. When they did, I took one out to look at it and was shocked to see the crimping cannelure was higher up on the shank. Took out an older one to compare and sure enough it was considerably higher. So I called Woodleigh to ask if there was a different bullet to accomodate my requirements and they said they had to change it to suit the then new 375 Ruger, I found this preposterous, they no longer had an option to suit a 3.6" COL, it was to suit the 3.34" of the shorter round in both 270g PP and 300g PP, the round nose bullets had not changed.
Nosler have done the same changing nose profiles and length in the past numerous times…

Cheers.

 

[MarkInPA]

I discovered a few minutes ago that Sierra released 2 different versions of this projectile, #4680 and #4681.

Apparently #4680 (which I have ) is designed specifically for 300wm/300prc and #4681 is for 308 Win and 30-06.

When I ordered these this was not disclosed nor was it available without some "google-fu".

Yep, I was just going to respond with this information. I have been tinkering with these bullets, the ones designed for .308's and .30-06's and they are long bullet. In my .30-06, I have to seat the bullets deep enough that the base of the bullet is all the way down at the lower shoulder junction. Even after you have the correct bullet, they have to be seated deeply.

I'm not sure how long my experiment with these bullets is going to last until I move on to something else.

 

[MarkInPA]

What ever it is worth, attached is Sierra's reloading data for the .30-06. They list an overall length for this bullet as 3.300"

Load data for the .308 Winchester should be available on their website.

 

[MarkInPA]

These bullets may be a good choice for a custom-built rifle with a long throat and long magazine.

 

[wvbearhunter]

These bullets may be a good choice for a custom-built rifle with a long throat and long magazine.

Mine is throated for the 195 tmk and using mdt mags which allow 2.89"

The weird ogive is the issue. I have never seen a .308 with an ogive so far forward.

 

[ARlife4me]

Going from their free online data 175's are only listed across all 30cals I've checked. Then I went to their bullet site and it list them as you've posted. Talk with Sierra about it and they could get you a refund or credit for the swap? I've had a similar issue with berger and they handled the issue w/o any problem(s). Problem i had was in their load data with a bullet published with a certain oal. It wasn't possible to seat at that short of length and I couldn't seat longer due to mag restriction. That kind of cs make want to buy from them. Sierra should be just as good to deal with.