Bolt Stick Big time

[338winmag]

Yup... reloading for a 300 Win Mag Custom rifle for Berger bullets according to their start and max powder loads.

Testing was very controlled and orchestrated so the concern of too many component changes does not factor into this I do so believe. Also previous components used in some reloads but powder charge reduced ....

Points in Question:
1. This was the thrid use of cases and some definitely tight chambering so they should have been FL sized before reloading this third time. (I need to pay more attention to this aspect)

2. I noticed primer pockets were very loose this third time seating with WLRMs. The first two reloads were using Federal Magnum Match Primers. I was also testing for the first time Remington 9 1/5 for magnums for 3 cases and they were fairly tight. (We never got to firing these 3 test rounds with the Remington primer)

3. I reduced powder throw for the H1000 by .5 grains from 74 grains to 73.5 because of one or two sticky bolts at last time at the range as well as changing the primer brand. Velocity stayed almost the same with the higher .5 load? Berger states starting load is 71.5 and maximum is 75.5

4. Was testing two different powders as well. H4831 at 1.1 grains over start load. Bolt stick also with this powder throw.

No other high pressure signs except one primer a little bit rough on its edges and possibly slightly dimpled.
Can the loose primer pockets cause higher than normal pressures causing sticky bolt by itself?
Was it the combination of loose primer pockets and the need to FL size cases before this reload?

Thanks for your time guys!
Steve

 

[358 Winchester]

Yup... reloading for a 300 Win Mag Custom rifle for Berger bullets according to their start and max powder loads.

Testing was very controlled and orchestrated so the concern of too many component changes does not factor into this I do so believe. Also previous components used in some reloads but powder charge reduced ....

Points in Question:
1. This was the thrid use of cases and some definitely tight chambering so they should have been FL sized before reloading this third time. (I need to pay more attention to this aspect)

2. I noticed primer pockets were very loose this third time seating with WLRMs. The first two reloads were using Federal Magnum Match Primers. I was also testing for the first time Remington 9 1/5 for magnums for 3 cases and they were fairly tight. (We never got to firing these 3 test rounds with the Remington primer)

3. I reduced powder throw for the H1000 by .5 grains from 74 grains to 73.5 because of one or two sticky bolts at last time at the range as well as changing the primer brand. Velocity stayed almost the same with the higher .5 load? Berger states starting load is 71.5 and maximum is 75.5

4. Was testing two different powders as well. H4831 at 1.1 grains over start load. Bolt stick also with this powder throw.

No other high pressure signs except one primer a little bit rough on its edges and possibly slightly dimpled.
Can the loose primer pockets cause higher than normal pressures causing sticky bolt by itself?
Was it the combination of loose primer pockets and the need to FL size cases before this reload?

Thanks for your time guys!
Steve

I have noticed that Winchester and Federal primers are slightly different in size, this may explain the loose fit in the primer pocket. Sticky bolt lift is one sign of high pressure, perhaps your rifle has a tight chamber.

 

[Guest]

You had pressure signs with 74, and you dropped back half a grain to 73.5. And you changed primers. And then you still had pressure problems. I think that's a fair summary of your post.

It seems pretty straight forward to me. Two things stand out. First, you should always drop back 5-10% or to the listed start charge whn you change primers. Second, you have been pushing pressure with 74, and that's a pretty sizable charge, so if you didn't change anything, you'd be well advised to drop back at least a full grain, if not a grain and a half.

Beyond that, you may have a tight chambered rifle. That is why start charges are what they are - they are designed to be safe in any rifle. Max loads are only safe if you've worked up to them.

 

[FOTIS]

Sticky bolt lift is one sign of high pressure,

YUP!

 

[JD338]

You had pressure signs with 74, and you dropped back half a grain to 73.5. And you changed primers. And then you still had pressure problems. I think that's a fair summary of your post.

It seems pretty straight forward to me. Two things stand out. First, you should always drop back 5-10% or to the listed start charge whn you change primers. Second, you have been pushing pressure with 74, and that's a pretty sizable charge, so if you didn't change anything, you'd be well advised to drop back at least a full grain, if not a grain and a half.

Beyond that, you may have a tight chambered rifle. That is why start charges are what they are - they are designed to be safe in any rifle. Max loads are only safe if you've worked up to them.

+1
Any time you change a component, you need to start low and work up.

JD338

 

[338winmag]

Thanks Guys.

I tried not to make the post a novel. We had literally started at "starting load" for two range outings. One slight sticky bolt out of 30 rounds from our custom rounds at 74 grains on second outing. Possible contribution to a rifle not cooling down enough at 92 degrees.

Also had some over the counter HSM rounds that were flying 200+ faster than our rounds. Sticky bolt lock too many times to ever consider the ammunition again.

I gleaned a couple of good thoughts from your posts.
"Beyond that, you may have a tight chambered rifle." -- This custom rifle never shows magnum cartridge bulge at the case head even after 3rd and 4rth generation brass. Every single big caliber magnum rifle I have reloaded (all over the counter), they start showing this around the 2nd or 3rd generation reload. In addition, thisrifle has shown light sticky bolt a few times with other over the counter ammo. The rifle might have 90 rounds thru it so far. When we called the gunsmith and mentioned this, he made the comment that alot of his custom rifles are tight and show some sticky bolt. I guess we took that with a grain of salt before. Now we will take that as a rule of thumb with this rifle.

"Two things stand out. First, you should always drop back 5-10% or to the listed start charge whn you change primers." Well I have heard that alot and maybe it is my math, but this percentage (especially the 10%) does not work out for most loads that often that I read for calibers I work with. Reducing by 3 to 5 grains often takes me back "well" beyond start charges for most. Yeah I know, "or the start charge whichever comes first" I was thinking .5 grain would have sufficed for the primer change. I believe you are correct in stating 1 -1.5 grain reduction. :wink: Point well taken and this 1-1.5 will be placed into my practice. :grin:

My mistake on not checking case chambering after the 2nd reload. It is now in my practice regime. I have found some tight chambering of some 270W and 30-06 after 2nd reloads for some over the counter rifles. Maybe 2 is a magic number.

"I have noticed that Winchester and Federal primers are slightly different in size" I now see this too with 2 magnum calibers. 358 Winchester's comment might very well explain this. The loose primer pockets do concern me but I cannot explain. I do know they were not this loose on the first or second firing so maybe these loads are showing some hot signs in this arena. What is a little confusing though is these same Federal Magnum Match primers showed loose seating in some brand new Winchester brass as well for another caliber.

I really appreciate everyone's comment. Being an engineer, I just have to add all posibilities. We have some virgin brass from the same lot. We will test ths scenario with the virgin brass and a couple of these loads this week and let you guys know.

Thanks
Steve

 

[Guest]

IN relation to the 5-10% and the 1-1.5gr reductions, I'll elaborate a bit on my thinking. All of this is relative, for the most part.

If I'm loading for my 8x57, and I get sticky bolt at 51gr, I might back that off to 50.5gr, depending on how sticky, and the ambient temp when I was shooting. But that's a reduction of about 1%. If I'm shooting one of my magnums where charges are more like 75-85gr at max, I'm looking for closer to 1gr reductions in the same situation. I suggested 1.5gr for your situation because you said the bolt was extremely difficult to get out of battery, and that makes me think it was well over pressure.

When I think of start and max charges, I usually go with an amalgam of the current manuals I have on hand, unless one manual has the exact combination I'm shooting. Taking that into account, I've got charge ranges (from start to max) of anywhere from 4-9gr depending on the chambering and the specific bullet weight. So I use the 5-10% or start charge rule. Using the 300Wby as an example, with IMR7828, start charge is 75gr and max is 80.5 according to Hodgdon. That's between 5 and 10%. Most lie in that area. For my favorite 30-06 load, H4350 and a 165gr bullet, start is 53gr, and max is 59gr (again, Hodgdon's data). That's over 10% difference between the two. The point is, when changing components - especially primers - drop back to the start charge, every time.

It sounds like you've got this well in hand moving forward, from your last post. Good luck on the shooting and I hope you find your velocity. Remember, though, velocity is fancy, but precision does all the work. And 200fps is going to make about 2" difference at 300yds, I bet.