Hard bolt lift mild load

[Pgohil]

7mm rem mag rem 700. 24" barrel.
Unknown Round count.

First load development for this rifle
New Norma brass
Fed 215M PRIMER
Nosler accubond 160
RL 22 powder
Book max is 65
.020 off the lands.

I loaded up rounds from 62.5 to 65 in half grain incriments to see what this rifle liked. The first couple shots the bolt felt a touch sticky, after that it became very stuck. I did not shoot it past 63.5 grains. No bolt swipe, no flatten primers, no cratered primers. Backed all the way down to 62 grains, I'm getting right at 2900 FPS, and just a bit of bolt stick. I can't understand what's causing this.

Today was hot, upper 80s and I was in the full sun reloading at the range for this development. I'm wondering how much the sun was causing an issue. But still I don't think it should cause extraction problems.
The 62 and 1/2 grain load shot incredibly well sub moa 2936 fps and SD 5 , But it does no good if you can't work the bolt!
I'd appreciate any help thanks.

Another thing I noticed when firing a string of three, the last shot was always the hardest to lift and extract That's one reason why I'm thinking heat is an issue.

 

[BrianB7mm]

I have never had that issue am curious as to what you find out from others. Also if you do the same procedure in the winter if it does the same thing, I like your theory about the heat from the sun.

 

[Trippy]

What book are you using? Nosler and Hornady list 63 grain RL22 as max from what I have.

 

[BruinPoint]

I see 63gr as max for a 160 Accubond as well. Alliant lists a max 65gr of RL22 for a Speer 160 but that may not correlate directly for an Accubond. Sometimes there are variations between lot #'s of powder, and having ammo sitting in the summer sun definitely could be a contributing factor.

 

[Pgohil]

I was using my Hornady book. I'll definitely start double checking back to the bullet manufacturers. Thank you!

 

[Harvey_NW]

I had issues with pressure below book max using H1000 and 160 accubonds in my 7 mag too, thought it was maybe just my rifle. Wonder if it's something with the design.

 

[Jeff_Gibbons]

Couple other thoughts/questions to help:
- did you check your scale?
- what is your coal compared to the manual?
- I've read that tougher bullets can increase pressure with same charge. Makes sense to me but my browning 7RM hasn't shown that to be an issue.
I get 3k with 160 SGKs in my 7rm with RE22 and no issues but it is hot for my coal/throat and charge.

 

[Rob5589]

Did you load a new empty brass by chance? Or size it first? How's the chamber look? I've run over your load with R22 and never had an issue with both a 162 and 180.

 

[Wrench]

Norma brass may buy you some free pressure also.

 

[D_Dubya]

Did you Check your brass trim length? A little long can make it sticky. Could also be a carbon ring built up but since you’re getting very consistent velocities that seems unlikely, though With an unknown round count I’d scrub it with iosso or JB just to make sure.

 

[Pgohil]

Couple other thoughts/questions to help:
- did you check your scale?
- what is your coal compared to the manual?
- I've read that tougher bullets can increase pressure with same charge. Makes sense to me but my browning 7RM hasn't shown that to be an issue.
I get 3k with 160 SGKs in my 7rm with RE22 and no issues but it is hot for my coal/throat and charge.

Yes, I check and calibrate my scale a couple times when I reload in the field.
I did not check COAL, good point. But it's seated 20 off the lands and fits in the mag well, do I didn't think about COAL

Did you load a new empty brass by chance? Or size it first? How's the chamber look? I've run over your load with R22 and never had an issue with both a 162 and 180.

New empty brass chambers and extracts just fine. Chamber looks good, but I'm not knowledgeable enough really.

Norma brass may buy you some free pressure also.

+1 I've heard this as well.

Did you Check your brass trim length? A little long can make it sticky. Could also be a carbon ring built up but since you’re getting very consistent velocities that seems unlikely, though With an unknown round count I’d scrub it with iosso or JB just to make sure.

I don't believe it's a trim length issue, but I'll check it for sure. It feels like it's the area just above the belt on the case that is sticking.

Thanks all!

 

[T28w]

Why will Norma brass increase pressure?

 

[Trippy]

Why will Norma brass increase pressure?

Different capacity different pressure.

 

[Wrench]

I stuck a 375h&h with starting load data. I had some extra heavy brass. It is an often discarded procedure to start liw and work high.....but one time in a thousand it pays big.

 

[BigNate]

I'm assuming this isn't a rifle familiar to you? First time work up & unknown round count.

Several good things to check have been mentioned. When I first start with a new barrel, or gun (especially a used gun) I always wonder if it was a problem child, or if new if the chamber is cut correctly. In your case I wonder about it being short throated. If it's an older barrel, the common bullets in use were not nearly as sleek and the ogive is a lot different. Are you sure you're .020" off the lands?

If it seems all is well, have you fired any factory ammo out of it?

 

[Pgohil]

Pretty familiar with the rifle been shooting factory ammo for 15 years., No issues. Yes 20 off the lands.

 

[long hunter]

Perhaps a sizing situation, I always size new brass prior too loading and also use a hornady case gauge prior too loading.

 

[Pgohil]

40 rounds on this bore

 

[BigSky]

Some new brass needs to be sized and some doesn't. I always check by chambering new brass to check how hard the bolt is to close. If it's too stiff, I size it a little to fit my chamber better. I also measure overall length prior to loading.

 

[Pgohil]

I sized the new brass b4 loading. Chambered just fine