.30-06 OAL questions

[41 Mag]

The only tidbit I'll throw out there is, and I don't mean to insult anyone's intelligence, make sure the bore is good and clean. Get all that copper and powder fouling out of there.

Amen to that. My pop's hunting rifle is a sporterized 03A3 he fixed up back in 62. His standard load was as follows. Pull the ball bullet out of the milsurp ammo, remove the primer pin from the sizing die and neck size, then seat a 150gr Sierra back into the case and go hunting. He used it to kill more deer than I have. After he passed, I pulled it out one weekend and cleaned it up. It took two days of soak and stroke to get all of the years worth of gunk out of it. I hauled it to the range after that and ran some handloads through it and low and behold several 1" 5 shot groups at 100yds and a couple close to that at 200yds. I just looked up and said, see what a good cleaning can do...

He' I am sure would have had a snappy comeback, but that was him. He was happy if they landed in a 3" group and I can honestly say he never missed. One thing you DIDN'T do was bet him he couldn't hit something with it.

utvolsfan77 I must have read right past where you posted those mag length measurements. I went back and see them now though. Yep you should be good on length in that for sure. When you might watch for, and I have two Rem 700's that this has happened with, there is a little gap right where the mag box comes up below the bottom of the chamber mouth. With both Nosler BT's and with the Hornady SST, in both of these rifles, if I get the OAL out too far, those sharp little tips will hang up on that tine little gap when I go to feed the round in fast like on a follow up shot. Guess how I found that out. :banghead: THey function fine when going slow and deliberate like at the bench or when simply chambering a round when going hunting. Throw in a pack of hogs cutting out across a pasture and the second or third shot jams up tight. Seat the bullet .015" deeper not an issue what so ever.

Just thought I would toss that your way in case your might be like that as well. Never had an issue with any other type bullet except those with the sharp plastic noses.

Good luck and I hope your groups shrink to tiny clover leafs. I know the powder and probably those bullets should be able to get you there. I have simply loaded too many different rifles with this powder and bullet weight combo that would do it.

 

[gamestalker]

Andrew has really opened up the process, and options I thought I had put to bed decades ago. His experience and knowledge in this particular area is well supported by fact and physics, and addresses the the average production rifle and chamber quite well.

I was introduced to jamming by a couple of BR guys about 30 years ago, and the results have been very effective and reliable. However, jamming is very possibly one of the most difficult by which to manage pressures, especially for a new guy. Additionally, there is almost always some velocity sacrificed when jamming. Why is this, well when you get to the point of touching, and especially when jamming, the duration of peak pressure is increased, IMO. As Andrew says, a lot of the process of loading for accuracy while maintaining acceptable peak pressures revolves around timing. For me, and for nearly 30 years, I've accepted this as just one of the trade off's of jamming for production rigs, something I've been re-evaluating over the last few months.

I'm not saying that I've hands down changed my approach, but what I am saying, is that jamming, or chasing the lands as it were, is by no means, the only means, or the best method by which to obtain optimal accuracy for a production rig, well any rifle really. Then throw into the mix a rather new reloader, and jamming may very well be the quickest way to introduce someone to an over pressure situation for the first time.

In conclusion, there is a lot to be learned from those with the experience and knowledge necessary to decipher the physics / science of a pressure curve.

GS

 

[Surculus]

Hey guys, I'm new to THR and fairly new to metallic cartridge reloading.

So, can you please go into detail exactly how one re-loads a paper cartridge? Because you clearly felt the need to be precise that you were only new to metallic cartridge reloading...

Hey, in all seriousness, good luck! Be careful, & don't get all caught up in reloading, remember, it's just a means to an end: spending less on ammo so you can spend more time out shooting, not stuck in a basement or garage...

 

[Andrew Leigh]

As GS points out my experience is limited to production hunting type rifles.

I would like to be a little provocative here, so no offence is intended, this is purely my experience helping others. Hunting rifles and hunters have specific dynamics, I will mention a few related to this conversation;

- Must be able to chamber round from a magazine easily - This means that the magazine may well limit the COL and if the magazine does not you certainly want enough leeway such that you don't have a stoppage on your follow up shot.

- Must be able to maintain reasonable accuracy at 100m. Any production rifle giving you 1MOA will see to it that you never starve nor will you need to track for very far if at all.

- Most hunters will dust off the rifle once a year and expect to deliver match performances with no practice. I shoot and hunt a little more but am in this category. Most will then go on to seek solutions for poor shooting performance in their loads.

Now with that as a background, hunters, in the pursuit of accuracy, rather than heading to the range and banging off 50 rounds in practice "steal" methods from our bench rest friends. One of which is getting as close to the lands as possible.

There are two primary reasons for wanting to be on the lands, bearing in mind you are not limited by a magazine ore bullet setback. The first is that this centres the bullet to the bore which is obviously desirable when striving for pin point accuracy. The other is to remove the variable of varying bullet length, seating depth and throat erosion. What us hunters fail to realise that the bench boys have custom cut chambers, hand lapped competition barrels, custom fit rifles and the list goes on. There is a nice book available locally call the "Accurate Chain" because accuracy is not determined by one factor.

It is appropriate to be on the lands with competition gear but inappropriate and can be dangerous to chase the lands as a hunter.

Recently I assisted guy with loads in a 7X57 and he could not drop under 1.4" groups. Exasperated I bedded the rifle for him and he recorded the same results. It then promised to re-bed the rifle (knowing the original job was fine). The guy was still disgruntled as he "knows" he can shoot better than that. The loads were developed in QL. Two weeks ago his dad comes to visit and off to the range they go. Dad shoots a 0.25" group followed by a 0.44" group, this at 109 yards (100m).

Many occasional hunters are unable to resolve any minor change in their load as their rounds down the barrel simply does not allow.

So my encouragement to the OP is to avoid the pitfalls of diminishing returns when reloading for hunting rifles. My 6.5 and 30-06 are both 0.08" off the lands, the 6.5mm does 0.60MOA and the 30-06 does 0.75MOA. My .375 is 0.28" off the lands and I get 1.0MOA with a best of .25" group at 109yards.

I would like to get a bench rifle one day and load into the lands .

 

[readyeddy]

1 MOA sounds good enough for me for hunting. Shorter COAL is not a bad thing. You get lower pressures, more easily fits in the magazine and promotes reliable feeding.

 

[ArchAngelCD]

1 MOA sounds good enough for me for hunting. Shorter COAL is not a bad thing. You get lower pressures, more easily fits in the magazine and promotes reliable feeding.

I agree with the above.

Riddle me this, Weatherby rifles are made is such a manner you can not get close to the rifling yet they are known for extreme accuracy.

Another note, 100 years ago hunters were shooting a 25-20 or 25-35 leverguns which on their best day would be a 3MOA rifle and yet our forefathers were able to feed their families. Their rifles didn't shoot tiny little groups, the bullet wasn't traveling fast enough to melt the jacket and they weren't shooting a 300 Win Mag or larger! I wonder how they didn't starve? All the marketing hype is taking the real meaning of a good hunting rifle away from us. Maybe they were able to take game because they really knew how to shoot and they knew what their rifle would do when they pulled the trigger.

 

[utvolsfan77]

Surculus, when I specified "metallic cartridges" above, that was in comparison to shotshells. Although I have been reloading shotshells for more than 40 years, I didn't get into reloading for centerfire rifles and handguns until about three years ago. lol

 

[utvolsfan77]

Well folks, I guess I must have misunderstood how pressure works when I read all of the reloading manuals then. I had always believed that if everything else remained constant except for the seating depth, the overall chamber pressure would actually decrease as the cartridge overall length increased. At least until the round begins touching the lands. At that point there will normally be a sudden and drastic increase in overall chamber pressure.

In fact, several manuals even state that you can gain case capacity, increase powder charge weight, and increase muzzle velocity while actually reducing overall chamber pressures by seating bullets closer to the lands. Of course, in order to do so, one has to exceed the SAAMI max.

So what am I missing or not understanding here? ArchAngel or Andrew Leigh, can either of you shed light on the subject?

 

[notaglockfanboy]

The reason you will get pressure signs when seating closer to the lands is because the bullet does not get the "running start" it would when seated deeper. I have actually gotten less pressure signs with more powder and asked the same question, and it turned out, for me anyway, it had to do with the seating depth of the bullet. A load that shows no pressure signs at near max with a COAL specified in your loading manual will start flattening primers and sticking your bolt when you approach the lands. Seems weird that when you increase case capacity by seating the bullet closer to the lands the pressures start rising, when physics tells you it should be dropping.

 

[utvolsfan77]

notaglockfaboy, there are two immediate problems with your last post.

(1) You stated, "A load that shows no pressure signs at near max with a COAL specified in your loading manual will start flattening primers and sticking your bolt when you approach the lands." From a general safety standpoint, it is my understanding that when a load is at or near maximum levels while using the SAAMI COL, the very first thing one is SUPPOSED to do before making any other changes is to REDUCE the charge weight, and then work back up in very small increments until pressure signs appear! Doing otherwise is simply inviting disaster.

(2) You stated, "Seems weird that when you increase case capacity by seating the bullet closer to the lands the pressures start rising, when physics tells you it should be dropping." This isn't always the case in what I've gathered reading manuals and several other forums. I think it comes down to the chamber dimensions of the individual rifle.

In my particular case, all rounds I loaded in the past were loaded near the SAAMI maximum COL of 3.340". I stopped at the maximum recommended charge. However, I have nearly 3/16" of freebore available beyond the SAAMI max of 3.340", so I will reduce my powder charge a couple of grains and work back up while seating bullets closer to the lands until I begin to see pressure signs.

Now that may or may not be the case with your rifles. Just because mine has a bit of free bore available does not mean that yours necessarily will.

 

[ArchAngelCD]

Just remember, it's a good general rule to have at least 1 full caliber length of bullet in the neck to maintain proper neck tension for the bullet.

 

[readyeddy]

Also, you don't need to be touching the lands to increase pressure. Pressure increases as you get closer. Stay safe brother. Dropping a couple of grains is a good idea.

 

[Andrew Leigh]

@readyeddy

Yes and no.

Earlier on in a post you stated that pressure reduces as you seat deeper in the case. I am afraid that this statement is simply incorrect. Pressure is a function of volume and as you reduce the volume in the case, for the same given load, your pressure will increase.

As you seat further out pressure drops until you reach a point where the inertia required to over come the lands begins to increase. Simply put a bullet well off the lands has a running start and overcomes the forces required to enter the lands easier than a bullet from a near standing start.

I did my own tests on a .308 calibre, I incrementally loaded in steps of 0.20mm and stopped 0.20mm from the lands. I fired three shot groups and recorded the velocity, the velocity was then converted back to a pressure.

So "Cartridge Pressure" is the QuickLOAD simulation and "Inertia Pressure" the actual pressure. Note to all QL users, QL does not factor the effect of inertia as you approach the lands only when you touch them.

So from 2mm to 1mm the change in pressure is smaller as the volume in the case increases thereby reducing pressure. From 1.00mm (0.040") off the lands the effect of inertia is very apparent and completely offsets the growing case volume in a near exponential fashion.



Cheers

 

[Andrew Leigh]

Riddle me this, Weatherby rifles are made is such a manner you can not get close to the rifling yet they are known for extreme accuracy.

To get the pressure and velocity up this could not be achieved with SAAMI chambering. They increased the free bore which allowed one to seat the bullet further out, due to the long free bore the inertia effect was dramatically reduced allowing for increased pressures. As stated I do not believe that jump is a function of accuracy, Weatherby proved is and so too does my .375.

Another note, 100 years ago hunters were shooting a 25-20 or 25-35 leverguns which on their best day would be a 3MOA rifle and yet our forefathers were able to feed their families. Their rifles didn't shoot tiny little groups, the bullet wasn't traveling fast enough to melt the jacket and they weren't shooting a 300 Win Mag or larger! I wonder how they didn't starve? All the marketing hype is taking the real meaning of a good hunting rifle away from us. Maybe they were able to take game because they really knew how to shoot and they knew what their rifle would do when they pulled the trigger.

Ammo in the old days was a precious commodity so every shot had to count. I believe that shots were better considered for this reason. Add to that the hunter of old was undoubtedly a more competent outdoorsman than the average hunter today and I will bet they were able to get significantly closer to the animal thus negating the lack of accuracy.

The young boers in South Africa were given one round and had to bring back the buck, simple as that.