Bolt hard to close with certain bullets

[Jeffersonian]

I have been reloading for 30-06, and in my Winchester XPR I have noticed something “funny”.

Certain bullets like the Hornady 150gr SST and the Sierra 168gr Matchking, even loaded to the COAL listed in the book, have resistance closing the bolt.

I am confident that this is not a headspace issue because I am using Virgin brass on. When I remove a chambered cartridge, there does appear to be a mark around the bullet so it may be touching the lands.

I’m thinking that my rifle may have a really short throat.

 

[gmr4]

Sometimes virgin brass needs to be sized, Measure them or better yet chamber 5-6 of them to see. This could also be a primer not seated flush or below flush.

 

[SSL]

Think you are on the right track thinking about a short throat. May have to bump the bullets back a little further. It won't hurt anything. COAL isn't an engraved in stone marker. It is meant as a guide, not an absolute. Good luck to you.

 

[ELR LVR]

Yes Virgin brass is not particularly sized to your specific chamber
FL size it
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Instead - take a piece of brass that WILL easily chamber
Seat a bullet into THAT piece of empty brass without a primer
then try chamber that dummy round with that known piece of brass
this will tell you for sure if the bullet is interfering with chambering
Marking with Sharpie is not the best way since little other things will scratch the sharpie mark
as you chamber
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Best yet : accurately Measure and make a Gauge for where you bullet touches lands :
Heres how: dont believe others who have challenges with things like doing fractions or playing guitar
I do things like study Quantum Physics in my spare time just for fun and memorize the
Square root of 63 out to the 15th digit past the decimal point so just trust me on this process
Insert cleaning rod into barrel from muzzle with bolt closed
Bottom cleaning rod against boltface
Mark the end of the cleaning rod flush with the muzzle
Next measurement
Insert your bullet you will be using into chamber (naked bullet only) and tap base lightly to seat in lands
Re-Insert cleaning rod from muzzle until it jussssst kisses tip of bullet (she likes that)
Mark this 2nd location on cleaning rod flush with the muzzle
Measure between these 2 marks
This is where the bullet touches the lands` and is OAL for touching lands
FOR THAT ONE BULLET -Save in freezer so you dont loose it
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The more accurate you are with your marks on cleaning rod the more accurate your measurement
I use small piece of electrical tape cut nicely with scissors
and align the tape perfectly flush with end of muzzle and apply tape to cleaning rod.
When you are done you will have 2 pieces of tape on your rod
Don't be discouraged, the rod can handle it
measure between the same ends of tape you aligned with the muzzle
not two different ends
Some people are not as good as me
Not my problem
Not your problem either, do it right and do it well, surface prep is key
I can get repeatable accuracy this way to within a couple thou
Often the same meaurement 3 times in a row
Yes I triple check this to double check how freakin good I am at this
--------------------------------------------
Save this one piece of dummy brass for all comparisons including Base to Ogive where you can now...
...have a reference for your seating depth from touching Lands and ALSO can use this as OAL for that one type of bullet, try not to fall for the hype of $330 dollar tools to measure bullets touching lands
as well as ---you may now use this dummy brass for,,,,,wait for iiiiiiit



--- Base to Ogive for all bullets
CBTO is the best way to measure C)artridge B)ase T)o O)give seating depth
as a matter of fact, CBTO is the only way to measure C)artridge B)ase T)o O)give seating depth
since the differing tips(Meplats) of bullets make OAL not the same
I have only seen Plastic Ballistic tipped bullets all be pretty much the same OAL
if it is not a tipped bullet OAL is not an accurate way of meauring seating depth and can be off as much .010" or more

 

[M-61]

You have measure from the base to the ogive of the bullet. The ogive is the ‘thickest’ greatest in diameter of the bullet. With Hornady in particular I’ve found it can vary with bullets in the same box. Sierra not as much, but (as always) is my experience. In fact in Hornadys light weight.308 bullets it was insane the variation.
Is this your problem? Not a clue. BUT COAL will tell you if if it fits in a magazine but that’s all it does. You may be surprised if you measure the ogive.

 

[divingin]

I am confident that this is not a headspace issue because I am using Virgin brass on. When I remove a chambered cartridge, there does appear to be a mark around the bullet so it may be touching the lands.

I’m thinking that my rifle may have a really short throat.

Are you getting a scuff mark all the way around the bullet, or little football shaped scuff marks aligned with the bullets centerline axis?

Scuff mark around the entire circumference is likely due to carbon buildup in the front of the chamber (the portion between the mouth of the brass and the end of the chamber.)

If you were just hitting the lands, you'd get a mark from each of the lands, but it wouldn't encircle the bullet.

 

[Webster]

I have been reloading for 30-06, and in my Winchester XPR I have noticed something “funny”.

Certain bullets like the Hornady 150gr SST and the Sierra 168gr Matchking, even loaded to the COAL listed in the book, have resistance closing the bolt.

I am confident that this is not a headspace issue because I am using Virgin brass on. When I remove a chambered cartridge, there does appear to be a mark around the bullet so it may be touching the lands.

I’m thinking that my rifle may have a really short throat.

Your seating the bullets to long.

 

[DShortt]

A picture is worth a thousand words.

 

[Orr89rocz]

Happens on my 338 and 6.8 western. Short throats. Saami or book load length with some bullets are jam.

I have two custom 308’s with similar chambers and a factory Remington with a very long throat, cant seat out to touch it. Idk how they can vary that much, tolerances be damned

 

[K22]

I never assume that the published Max COAL is absolute for every rifle. The first thing I do when using a new bullet and / or a new rifle, is measure the base to ogive dimension. I do this initially for every rifle and every different bullet I intend use.

Case in point. For many years I used the great Sierra 85 BTHP in my 243 Win Remington Rifles. Never had a problem with bullets jamming into the lands.

I purchase a Tikka 243 and just assumed that the COAL I've used for years (2.670) with a lot of success would be a good place to start load development. Since the published SAMMI Max COAL is 2.710, I never anticipated any problems. WRONG!

When I got to the range to test some loads, the cartridges would not chamber. When I extracted the live round, the bullet stuck in the lands and powder was poured into the magazine and action. What a mess!

After measuring the actual base to ogive (Frankfort Arsenal method), I learned that the MAX COAL for this bullet / rifle was 2.630. From that point on, I always measured the base to ogive whenever I use a new bullet for an existing rifle or when I had a new rifle.

 

[DShortt]

It would be fairly easy to deduce where the interference is with a couple of pictures.

Otherwise, it's just guessing.

 

[gmr4]

Both Alex Wheeler and Eric Cortina have videos on how to find jam.. wheeleraccuracy.com. Anyway you partially seat a bullet with your seater… then fully seat it in chamber with the bolt.. no primer of course. You will need to strip the bolt first. I do this method with each barrel and each bullet type this is the Cortina method, I beleive. Wheeler bumps the bullet back by couple thousants at a time until there is no clicker…

 

[M-61]

Apologies for the “give” instead of “ OGIVE”. The spell check is an easy way to blame it but what the heck is wrong with re-reading what I wrote before I post it!
I think it’s me slipping.

 

[DShortt]

With 9 posts since 2021, I suspect no pictures are forthcoming, or any other information for that matter.
Just drop a problem and go away for months.

Nice.

 

[Ackman]

By now you should have this figured out. But I'll pretend its a new post.
You need to find where the lands are for each bullet you use. It's easy. Make a split neck case. Take new case, inside chamfered, and split the neck with a dremel cutoff wheel. The whole neck length and into the shoulder. Also drill out the flash hole to something larger.
Adust the neck tension so a bullet goes in with not much pressure. Chamber it, then eject carefully and measure with an ogive checker. Mine are Davidson from the 80's, one for every caliber. Hornady makes a nice kit now. The picture shows this. That's the ogive contact point with the lands......for that bullet. With a little practice you get to know how much squeeze to put on the case neck, and how much pressure to put on the caliper wwhen closing it on the bullet. Very easy. Check it a couple times til you're confident youve got it right.