Hard bolt lift but not every time

[Rem06]

I’ve got a new rifle in 6.5CM. Loaded some 140’s in new starline brass with cci450 primers from 41.5-42.3gr. I had hard bolt lift on a few in each charge weight, but not all.
Also had it with factory Hornady whitetail 129, but not with every round.

What would cause this? The rounds that did have a heavier lift, had slight primer cratering and ejector marks.

rifle is a bergara premier series

Are you full length resizing and bumping shoulder 3-4thou ?
Case body usually causes hard bolt lift or the double click lift.

What dies are you using? Is it sizing the body enough?

 

[Nomad88]

Do you have velocity numbers here?

Yea.
41.5- 2758
41.7- 2783
41.9- 2797
42.1- 2817
42.3- 2825

 

[Nomad88]

Are you full length resizing and bumping shoulder 3-4thou ?
Case body usually causes hard bolt lift or the double click lift.

What dies are you using? Is it sizing the body enough?

Redding dies, bumping the shoulder .003

 

[Nomad88]

Figured id show what I got in the deer blind lol.
Decent doe at 150 yards moving with a 16” 6mm arc 90gr eldx

 

[NATE49]

I’ve got a new rifle in 6.5CM. Loaded some 140’s in new starline brass with cci450 primers from 41.5-42.3gr. I had hard bolt lift on a few in each charge weight, but not all.
Also had it with factory Hornady whitetail 129, but not with every round.

What would cause this? The rounds that did have a heavier lift, had slight primer cratering and ejector marks.

rifle is a bergara premier series

@Nomad88 i can understand falling into a pattern of “they all like that load” if they’re all the same barrel maker and number/diameter of grooves and cut with the same Reamer, but that’s not the case here.

Back way off, do a seating depth test, then some powder work.

Some factory ammo can get blown/ flattered primers, it can depend Greatly on temperature, Military long range shooters have put standard ammo in the sun to get more distance. I have opened many a bolt with a mallet hot ammo barrels so on
Extend the seating depth as long as possible and still shut the bolt on an empty sized shell jam it and keep pressure within specs but increasing case capacity can greatly reduce pressure while beginning to work on a load

 

[fkimble@charter.net]

The primer corners are still rounded. I don't think its a hot load in you gun even if s little over book max. The raised ridge around the firing pin dent is most likely due to an oversize firing pin hole in the bolt face or a weak firing pin spring. May want/need to get firing pin hole bushed and pin tip reduced to match.

Frank

 

[Clancy]

The primer corners are still rounded. I don't think its a hot load in you gun even if s little over book max. The raised ridge around the firing pin dent is most likely due to an oversize firing pin hole in the bolt face or a weak firing pin spring. May want/need to get firing pin hole bushed and pin tip reduced to match.

Frank

You don’t see the giant ejector marks?

 

[Stumpy1]

Chamber walls too smooth (too finely polished)?
Brass still has some lube on the body?
Combination of both?

Just some thoughts on the matter.

Frank

 

[6BRA]

After cleaning gun, always clean chamber with alcohol soaked patch getting rid of remnant bolt grease cleaning solution. Wipe case lube off case with quick alcohol pass. It allows chamber walls to hold brass and help prevent bolt slam / case head smear. Of course once your too hot nothing will help. From your velocity I don't think you are overly hot. Jmo

 

[Kracken McGraw]

I know everyone wants to get the most they can from this cartridge, but let’s not tiptoe around what we all learned in the first pages of every reloading manual published ( how to look for over pressure signs in your brass).
Maybe this is as simple as the Starline SRP brass doesn’t like that much powder.

 

[BoydAllen]

All of this advice for someone who didn't even say what powder he was loading? Fellows, there is a minimum amount of information that anyone needs before giving realistic advice. I think that in cases like this that the first responder should have asked what powder, and everyone else held off until that was given.

 

[bichettereds]

All of this advice for someone who didn't even say what powder he was loading? Fellows, there is a minimum amount of information that anyone needs before giving realistic advice. I think that in cases like this that the first responder should have asked what powder, and everyone else held off until that was given.

It looks like the first responder did ask what powder, and the next post was the OP responding with what he is using.

 

[joshb]

I know everyone wants to get the most they can from this cartridge, but let’s not tiptoe around what we all learned in the first pages of every reloading manual published ( how to look for over pressure signs in your brass).
Maybe this is as simple as the Starline SRP brass doesn’t like that much powder.

Yup! Don’t replace the fundamentals of reloading for one gun with experience from loading other guns. Work up! Don’t assume.

 

[jsn]

Lee's manual shows 41.5gr as the max load for H4350, that's Hodgdon data (142gr bullet).

Hodgdon shows 40.0gr and 40.4gr for two different bullets with 2,700fps as max.

Maybe the throat/freebore is different from you other rifles also?

Which bullet and have you checked the diameter?

 

[6.5 forever]

Oou-wee! Look at them ejector prints.

This is the number one sign something is wrong!!

 

[BoydAllen]

Referring to my earlier post, evidently I need to slow down my skimming a bit. One more observation, If you get one tight lift with a definite pressure sign, stop. Brass is not identical so it does not get tight at the same exact pressure, but if you get one in a set that is tight you need to figure out why before continuing.

 

[SD guy]

Yea.
41.5- 2758
41.7- 2783
41.9- 2797
42.1- 2817
42.3- 2825

Is this the 140 grain load using H4350? What charge weight? What barrel length?

Opportunity to learn here I suppose. Where did you get your load data? what is your seating depth? do you have any idea how much jump to the lands you have?

What were you expecting for velocity?

Hodgdon online load data can be a great resource. Though start low & work up. With the limited information provided I am inclined to start off with 101 Start low & work up. If your velocity is high then the pressure is likely high. Barrel length needs to be considered when assessing velocity.

Not to say the bolt lift is not another valuable data point that suggest over pressure. Back off & work up accordingly.

 

[358WCF]

I've had a couple rifles over the years that left ejector marks even with start loads, but not in conjunction with hard bolt lift unless I leaned too heavily on the powder measure. Good idea to find the cause before proceeding.

Starline may have less internal capacity than Hornady brass.

FWIW, in addition to the other possibilities mentioned above, I've seen a fairly large swing in H4350 from lot to lot over the last few years.

The most notable was in 2020 when I got a pound each from 2 different places within a month of each other. In a 22-250 Ackley identical charges with all other identical components shot the same day there was 200fps difference between the 2 lots.

Using the same 2 cans of powder, there was smaller velocity loss, but still similar a difference in 3 other rifles... 7x57, 338-06 Ackley. & 358 Norma Mag. So... it wasn't a fluke.

 

[M-61]

Redding dies, bumping the shoulder .003

How did you determine.003 was the number needed?
In my experience the only time I would bump at all is failure for the bolt to close and chamber the cartridge smoothly. And before I would do that I’ll resize the case and let it sit in the die for 3-5 seconds. Usually solves that. I only br shoot and I’ll chamber every reloaded round upon completion to eliminate a surprise at the range.

 

[J_idaho]

For factory ammo to stick you have a rough chamber.