Scratches on Bullet

[SR Burton]

A puzzler. I'm shooting my Remington 700 in 30-06. Last time out I had a couple rounds the bolt would not close on. That had never happened before. I've had the rifle for 5 years. Before taking it out again, I cleaned the barrel for copper fouling with Boretech.

Today it happened again, three times in 20 shots. The bolt won't close, the bullet will not extract. I had to push a wooden dowel through the muzzle to punch the bullet back into the internal magazine.

Here are the known factors: Bad bullets are the same OAL as the ones that fire fine, 3.30". Same with the case length, 2.48". All bullets are handloads with SMK 168 gr and new or once fired Lapua brass. All once fired are full length sized with the same Lee dies I have always used. They all also have a light crimp with the Lee crimp die. The scratch marks are all the same distance above the case mouth, 0.15".

The scratches only appear on one part of the bullet, as shown in the close up photo. They do not go all the way around the circumference of the bullet.

Any ideas on the cause?

 

[biker_bill]

Would bet the ogive is different because all the bullets aren't the same.
That round went too far into the barrel, those marks are from the lands and grooves.
Pressure would go way up.

The OAL of that bullet should be less than the others.
By the distance to those marks, plus a couple thousandths.

 

[optimumdetails]

Looks loaded into the lands. Get a comparator for the caliber you are loading. The scratches are from where the bullet is hitting the rifling. I would weigh your bullets and make sure you didn't mix some together

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[optimumdetails]

You can also order a borescope off of Amazon for about $75 and check your barrel

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[SR Burton]

You can also order a borescope off of Amazon for about $75 and check your barrel

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Funny you mention that, I just ordered one yesterday off Amazon for that very reason. I’ve also had the Hornady comparator for a couple years now. Haven’t used it in my reloading lately, so I need to get that back out.

I’ll pull and weigh the bullets that did not seat just to double check.

The consensus seems to be bullets seating into the lands so I can now focus on that. Thanks for the input.

 

[Frankmako]

if all of the other factors are the same,,,, case length, bullet length, and oal. then it might be the bullet, the bullet is fatter or out of round.

 

[SR Burton]

if all of the other factors are the same,,,, case length, bullet length, and oal. then it might be the bullet, the bullet is fatter or out of round.

That could be. Bullets that fire and those with scratches are all mic'd at .309 at the scratch location. What I can't measure is if they are out of round. Since they only contact the lands on one small part of the bullet, maybe that is the out of round spot.
These are all SMK 168, so they have been touched by the hand of God. Surely he does not have a QC issue.

 

[Ruger34]

I had some look like that when I tried to chamber a 308 round in a 7mm08!

 

[gh1950]

How much have you shot this rifle? I would be concerned about bore erosion because of the partial circle of marks.

Even loaded "long" you should have a uniform ring of marks.

Might be some fouling.

 

[ReservoirDawg10]

Check concentricity. Check your OAL. Check for carbon fouling.

If loaded too long, the marks should be equal all the way around.