Home Forums Hunting & Shooting Ask The Gunwriters Pressure signs.

My thought process is, once the gun is in hand and the target game decided, I ask myself what is the limiting factor on this setup. Is it the rifle, or is it the brass? If it's a strong modern bolt action or single shot, then the brass is the concern, and monitor the brass most closely for long life. The chrono and reference books are useful tools, but again, I've seen brass fail in cases where the book and the chrono said it was a good load. You also have to consider the bullet. You could safely launch a .30-30 bullet out of a .300 RUM 1000 fps faster than its design velocity, but obviously, it's not going to perform properly.

Perhaps someday I'll obtain a pressure measuring gizmo, to add to the toolbox. If the action is old or of lesser strength, then the brass may not the limiting factor in load development.

To me the craft of handloading is one of making high quality ammo, that accurately launches projectiles appropriate to the task. The ammo should safely utilize the full potential of the gun, while still keeping an appropriate safety margin. To those ends I'm going to use judgement, and a variety of tools.

This explains why the primer pocket grows faster than the OD of the brass. It does not matter how hard the brass is.

The same thing is true of the chamber of a firearm, except that we take care to keep the steel within its elastic limit. The inside of your chamber experiences higher strain and expands more than the outside of the chamber. The thicker your barrel, the greater the inside strain.

Yours is the goodest answer! Well said! But people won't believe you. Most want an overly technical answer that they don't really need or understand. Perhaps you could re-word it so it sounds, you know, erudite and overwhelming.

P.S. I did have a Shooting Chrony once that liked to embellish the truth.

I used a Shooting Chrony for quite a while, but got way too many Err messages and sometimes obviously bad velocities. I took MDs advice and got a Pro Chrono a couple years, ago and it is much more consistent and reliable. I know still a cheap chrony but it's working for me.

CZ550:

I suspect it took a man's man to handle those 45-70 loads. Have my Marlin jacked up to 1750 fps with 400 grainers, and it's not fun. That will be revised with their next loading.

Ringman, is that you?

You'll have to provide a finite element analysis to support this. (jk)

That would be great fun! So far, I still lack the software.

I've been following this thread w/o comment till now.

What I'm 'fixin' to say illustrates my progress as a handloader SINCE joining the 'fire'.

"The best 'pressure sign' is NO pressure sign!" ( you may quote me ifn you're amind to)

Research average velocity for cartridge/bullet/bll length - chrono till you get there.

There are no good replacements parts for eyes, nose, fingers, etc.


Jerry

There is absolutely nothing about an extra 75 fps that makes a 'maybe' sticky load worthwhile for hunting. Standing around admiring the shot with an empty case in the chamber has never proven to be an effective method of ensuring great outcomes. Sticky cases might not cause one to stand around, but the effect is just as 'worthwhile'.

There isn't a hunting situation where I'd take 100 fps more given other issues. Its really just not needed.

I do have to learn how to cycle that bolt though for the future.....just not a thing that I do down here.. but I know I have to learn to change... won't take much though.

Let's throw this question out there. Ok you get your manuals out, find a top end but reasonable target velocity. set up chrono. and go to work only to discover your falling like 2-300fps short of listed velocity with listed max charge. With same powder, cases primer , bullets ,COAL ect. so you start going over book max. charge 1,2 ,3 grs. when do you accept you have a slow rifle or maybe ultra smooth (slick) barrel or other reason to not build the pressure to reach target velocity to where you need more powder to reach pressure ?

When you get "pressure signs" ! !






Seriously I don't have a definitive answer to your ? That's a problem I've never encountered BUT I know that others have.

Mr. Denton ? Mr. Mule Deer ? et.al.


Jerry

KINDA OF MAKES ONE SAY UM , For me the annoying one is 70gr 243 NBT Nopsler list a bit over 3600fps I,ve alwys gotten they accurate load to shoot well, but never much over 3400fps this has been in several rifles, even taking in to account barrel length deducts.

I have never had a firearm that gave velocities far slower or faster than expected, so I've never been able to experimentally test the question.

I've seen a Sierra tech rep express that you can add powder until you reach rated MV.

That's probably dangerous because with some loads, MV reaches a point where it does not increase with more powder. That happened to me with a 308 and 2520 powder.

jwall,

Faster or slower velocities than expected are common in rifles chambered for some old military cartridges, especially European rounds, because throat length varies considerably. The original military throat lengths for the 6.5x55 and 7x57, for instance, were designed around very long round-nosed bullets, while some (but not all) modern sporters have much shorter throats. The 8x57 can also vary: While the original chamber had a very long throat for the typical heavy roundnoses, it was eventually shortened for the later light spitzer load--but some later civilian sporters also had longer throats, because in the early days of soft-nose cup-and-cores many hunters preferred long, heavy bullets for their superior penetration. I have just such a German sporter with all the usual touches such as double-set triggers, slim stock with side-panels and Schnabel forend, etc, and its throat is long enough to swallow 250-grain Woodleighs Weldcores with no trouble.

But even modern rifles can have slightly varying throats, or bore dimension. I've handloaded for more than a dozen .270 Winchesters, and the same loads would produce anywhere from 2900 to 3100 fps with 130-grain bullets and various appropriate powders such as IMR4350 and RL-22. If I ran into a slightly "slow" barrel that wouldn't get 3000+ fps with a 130, I added more powder to get there, and never have run into apparent pressure problems--even in a couple of rifles with 20-21" barrels. However, have also loaded for a couple of .270's that got 3100 fps with listed data, and since I didn't see the need to go for more, I quit there--unlike some handloaders who think any load that's apparently "safe" during one test will always be safe in all conditions.

One of the reasons I use a chronograph when working up loads is that, like Denton and the Sierra tech, I've also been told by more than one pressure-lab tech that adding a little powder to loads that produce lower velocities in a given rifle is a safe, as long as velocity was within "normal" boundaries.

That's kind of what I've always done when velocity quit going up with increased powder charges or went up very a little. I started going back down until the velocity starts dropping back off and call it done

The 338 Win Mag is another one which seems to get leaned on pretty hard sometimes, a deal which makes little sense to me considering the applications it often gets applied to...where reliability is paramount.

Id -

I had a 'different' situation that involved 'noticeably' less velocity (-200 fps) than I HAD BEEN getting. I am going to drastically reduce this story to get to THE answer.

This was @ 1990. I was shooting a 270--130 gr.--with a load that was KNOWN for an honest 3100 fps. I was shooting the same components - maybe a different lot # - BUT some new cases from a reputable maker. I had the loads ready so when I went to chronograph some other stuff, I thot I'll just check those loads out of 'curiosity'.

CURIOUSLY what had been going 3100 was ONLY 2900 ! ! Shaking my head, scratching my head ? ? ? LONG story short. I double checked the powder---and---primers separately. This took a couple of weeks of loading and graphing. Then, as a last resort) I RE-USED those same components in OTHER brass.

The load was compressed so there was NO adding powder to the charge.

Bottom line - the NEW brand of brass cases was THE culprit. Yes! !- I lost 200 fps in those cases ALONE.


I have since used that BRAND of brass with NO problems. There was some lot/lot variation or problem. For a few years I refused to buy that brand but 'eventually' I tried some others and they work fine.

I know this doesn't answer your ? but it shows queer stuff does happen.

Jerry

Queer stuff w/ a .270? Goes without saying . . .