Deep seated issues?

[longrangehunterII]

Over the years I've loaded a lot of different bullets in a lot of different calibers. One issue that I hear pop up is either their COAL wont fit into their magazine and/or wont get close enough to the lands in their rifle. Sometimes causing their load to have the bullet deeply seated into the case. Which I have noticed myself and either tuned the gun any way or looked for another bullet that fit the criteria and the case as well.

This is something that has kept me from using more then a few bullets in various calibers as of late. A lot of them are geared towards the heavy for caliber end and the high BC that comes with that. What I've noticed is that the tuning becomes far easier and the results better when the bullets aren't seated so deep into the case. And that last powder that worked for you in one weight bullet so well should work for another bullet in that weight class just as good, maybe.

Look at the first photo, here you'll see (4) bullets in one small cluster, looks like three but that's four bullet into that hole. You'll see on the paper roll from my Oehler that there was a total of (7) shots fired. The other larger group was fired from 300 yards, but I got the dope a little wrong. They were suppose do be dead center. This load only took two rounds to check the speed and the other five to check the load for accuracy. So you can see without a lot of fuss another load can be developed with out too much trouble if you had another load that worked before and switched the bullet with minor changes in powder charges made.


Seating depth can and does make a difference to load development for accuracy, and if you can run them close enough to the lands as the throat wears out you can chase the lands later on. I was going to chime in on another post about the importance of seating depth as well as which powder is being used in combination with the bullet to produce an accurate round, but I thought I'd stay out of it in that post. But I do have some results from this past two weeks in two different guns that show the same results. Getting the bullet close enough to the lands and avoiding a bullet that's too long for the case.

Photo #2 shows a loaded 7mm-08 round with a 168 grain Match King and that same bullet next to it showing the seating depth in the case.

In Photo #3 a different gun was used, a 6.5/300 WSM using a 140 Match King where the bullet is seated in the same position as the 7mm-08 round with the 168 SMK. What you'll see is the difference of only 0.010" in seating depth between the two groups. Nothing else was changed other then the seating depth. This is another load were I already had a great load using a hunting bullet, a 140 SGK, and switch to another bullet in the same weight and low and behold found another load only using ten rounds. The better group was BTW seated off the lands the same as the hunting bullet I had already developed.

Hope that helps about any deep seated fears you might have lurking in your minds, but in the end nothing is cast in stone. These are my own observations and what I have noticed is that deeply seated bullets can cause some issues other then how long the magazine box is, and bullet jump can make a difference in a loaded round for accuracy.

On another note, I've found the best accuracy near the upper end in terms of velocity (pressure), and avoided the mishaps that can happen when using the hottest loads due to temperature and elevation changes that can and do cause problems.

 

[AZShooter]

Looks like you are having fun shooting and collecting data. The more I load the more I realize that there are so many variables that combinations that shouldn't work often work just fine.

I used to be bothered by short magazines and long bullets WITH throats that were untouchable.

I also used to dismiss the idea of changing seating depth as the last tweak to obtain accuracy that Rick Jamison suggested a few decades ago.

I have never experienced any issue with elevation changing pressures. Also have never experienced issues with deeply seated bullets other than occasional poor accuracy.

I look at each rifle as an individual loading problem. I will load up the bullet and give it a try regardless of magazine length or distance to throat.

Many hunting rifles WILL shoot fantastic groups with many compromises. As long as the rifle is sound I feel it can be made to shoot.

Many here will attest to the finicky nature of VLDs. Most think the bullets need to be close or into the rifling to work. Not true. Even Berger makes suggestions to try various seating depths. Personal experience with a few 257 weatherbys and the 115 VLD have changed my mind on the distance to throat. Hybrids are so easy to load that I never bother to measure jump to rifling just seat to feed from mag box and work up a load.

I put together what might be considered an impossible combination for my friend's 300 WSM Browning A-bolt. Mag box was 2.8", and the 230 gr hybrid. No powder space right? Well this rifle shoots the 230s quite well from a 7 1/4 lb Browning A-bolt! RL-17 lit it up for a vel of 2725 from its short barrel. see pic.

The more I shoot the more I realize there are many combinations that many say "won't work" but do in fact work just fine. Short necked cartridges, long jump to rifling, no powder space, short barrels, and heavily worn barrels WILL SHOOT. After 30 yrs of reloading I can only conclude that a weird combination is worth a try.

 

[longrangehunterII]

I've had first hand knowledge of what can happen with hot loads developed at 203' above sea level and then fired at 6,000'-13,000' on a warm hot day..... blown primers! More then once I might add, but those weren't loads I developed, made me realize not to hot rod a round just for the sake of turning heads while out hunting. I just have to scratch my head when I hear a guy say his 6.5/300 WSM is running 3400 fps and I'm shooting the same cartridge and I clocked my own load using the same powder, same wight bullet and I'm fine shooting a 140 grain bullet at 3150-3200 fps. Seems odd, maybe I'm just too cautious?


I also stated that I have tuned guns using bullets that were deeply seated and couldn't reach the rifling. But my point was it can be easier when you at least have the option of working up a load that's within 0.00"-.070" of then lands fed from the magazine and don't have to use a bullet seated below the neck shoulder junction.

Compressed loads are and have been widely used over many decades, and are actually a better choice then a powder the doesn't fill the case as much in my opinion. But that's not what I was trying to address. It was a study about the internal ballistics with regards to the relationship of bullets being so deeply seated in a case, and the ease of tuning that load when they aren't.

I'm certainly not the first person to address this issue, but common wisdom as been what actually happens inside a case with regards to the gases developed during the burning of the powder, and the effects that take place to push a bullet from the case? I was attempting to show the effects of seating depth to the lands, choosing a bullet that doesn't encroach completely into the body of the case, and the length of time developing a load?

 

[AZShooter]

Thanks for the clarification. I agree it is easier to work with a cartridge with ample magazine room and a throat that isn't 3/8" like the old weatherbys.

I disagree on elevation causing excessive pressure. I asked this very question of Bryan Litz and he said flat out that elevation is not going to cause a change in pressure. You said you shot hot loads on a warm day. I'll go with the ambient temperature causing the issue not the elevation.

Nice to get to talk to another handloader that is into the details like you.

 

[longrangehunterII]

Hey Thanks AZShooter,

I am by know means going to imply I am an expert, and Bryan Litz is a smart guy. I've read a lot of his stuff, and agree with his statements and findings. Part of the reason I mentioned about keeping the bullet close to the lands and then chasing them as the throat wears has been the wisdom of more then a few benchrest shooters, and Bryan himself stated that would be best at the Shot Show when asked about loading his new line of bullets, and finding a seating depth that works.

Here's an article by a guy that shot more then a few matches that I've also followed his findings and have used in my previous test with my 7mm-08 for shooting out to 1,000 yards.

The Rifleman's Journal: Cartridges: 1000 Yard .308 Load Development

In part four of this article he shows more on the relationship of a bullet in a .308 case neck and two different chambers. Which I have read about before, and discussed with a few top benchrest shooters, but shows what I was trying to attempt in a different case and bullet but achieve the same results? Here's part four.

The Rifleman's Journal: Cartridges: 1000 Yard .308 Case Capacity and Other Problems

I can't say for certain about elevation and pressure, but the thin air effects a lot of different things that burn fuels and their output. Like I said, I didn't develop those loads, but I do know who did and where, but I had assumed more then once that the elevation must have an influence on the burn rate of a powder in a case? After all appliances that burn fossil fuels have to be calibrated. Maybe it's not the same? Lets ask this question, is the air inside the case sealed from the outside air once a loaded round is made? Can that air within the case allowed to expand and contract depending on atmospheric conditions outside? Does the atmospheric pressure effect how the powder within the case burns compared to where it was developed at sea level? I am well aware of how hot and cold effects the powder within a case when fired, but is it conclusive that elevation has zero affect on that pressure? I could be wrong, but I still wonder how that has no effect what-so-ever when it comes to gun powder confined within a case.

I am not trying cause an argument, but I do look for conclusions as to why things do what they do in any given situation?

 

[AZShooter]

LR Hunter II,

I'll read those two links by German Salazar tomorrow morning with my coffee. Have read some of his stuff in the past and enjoyed it.

Smokeless powder creates its own oxygen. What little air is trapped in the case is inconsequential compared to the expanding gases formed as the powder burns.

One of my friends is a 1000 BR shooter. He is always chasing the lands with those rifles. He and I banter around ideas and we have come to the conclusion that is best for BR accuracy. On the other hand we both agree that some jump is better for a hunting rifle. Even more bullet jump seems to make the load less subject to changes in velocity and group size than a bullet placed closely to lands as the rifling wears away.

After over 30 yrs of reloading I still enjoy doing it. It is fun tweaking the variables then observing the results at the range.

Ross

 

[longrangehunterII]

One of my friends is a 1000 BR shooter. He is always chasing the lands with those rifles. He and I banter around ideas and we have come to the conclusion that is best for BR accuracy. On the other hand we both agree that some jump is better for a hunting rifle. Even more bullet jump seems to make the load less subject to changes in velocity and group size than a bullet placed closely to lands as the rifling wears away.

Ross

I've noticed that as well, and who wants to find a bullet stuck in the barrel and gun powder all over the inside of your action when out in the field and/or some huge pressure spike that can happen with bullets jammed into the lands The only time I'll place bullets into the lands is for fire forming brass in an improved chamber.

The rifles I use aren't Bench Rest guns but hunting guns that would fall into the hunter bench rest category. I do and have taken some long shots at game animals, but I have too much respect for the "what if " to shoot beyond 600 yards on a living animal. I do shoot steel targets I have further then that. Even today at 600 yards I made a first round hit, missed one, hit it again, missed twice and then hit it almost dead center on the last round sent. 50% success.... not acceptable on a big game animal if you wound it, who cares if you miss?

Anyway, thanks Ross for the info. Enjoyed hearing from you as well.