Screaming Stupid Loads in 30 Cal?

[Ned Ludd]

Why would anyone resort to using 4000 fps .30 cal projectiles to obliterate a prairie dog town when there are much better thermobaric or plutonium-based alternatives?

 

[wboggs]

You need a longer barrel, V-max would lose it jacket if spun too fast

How does a longer barrel prevent bullet disintegration?
I was under the impression that a rough barrel and rotation spin were the major factors.

 

[Beiruty]

How does a longer barrel prevent bullet disintegration?
I was under the impression that a rough barrel and rotation spin were the major factors.

You are correct, a longer barrel does not prevent bullet disintegration. A slower twist rate would be needed to make a powerful magnum rifle reduce the bullet spin rate at the Muzzle.
A longer barrel is needed to achieve a higher MV with a slower burning powder

 

[Beiruty]

Why would anyone resort to using 4000 fps .30 cal projectiles to obliterate a prairie dog town when there are much better thermobaric or plutonium-based alternatives?

A question of curiosity I guess.

 

[wboggs]

You are correct, a longer barrel does not prevent bullet disintegration. A slower twist rate would be needed to make a powerful magnum rifle reduce the bullet spin rate at the Muzzle.
A longer barrel is needed to achieve a higher MV with a slower burning powder

There is a formula to calculate spin. The major companies will give you the limits for their bullets. Using cup and core most say over 300000 will eventually result in failure. I have blown up many out of .22-6mm with a 1-8 at high velocity. The answer is a mono bullet
I recently tested some 85g hammer hunters out of 6.5 with a 1-7.5 twist at 3800+ with excellent results.

 

[Beiruty]

Hornady has now the CX line of bullets
Here is their 0.308 110gr projectile

A bonus with mono bullets is that fly down the barrel faster due to less friction. Thus, a 110gr mono bullet can gain an extra 150 fps at the MV from 30' barrel, or 4150fps.
In a 26" barrel, 4000fps

https://www.hornady.com/bullets/rifle/30-cal-.308-110-gr-cx#!/

 

[wboggs]

Load them up and let us know your results. Groove design will play a large part in the amount of friction.

 

[Beiruty]

Load them up and let us know your results. Groove design will play a large part in the amount of friction.

Once I lay my hands on a box at local Cabelas I will do so.

It is a 600 yards monster of projectile

 

[Capt. Oblivious]

I played with 125gr BT's in my 300WM for fun, could get crazy speeds but the accuracy was never really there, around 3400fps they were scary accurate and dropped allot of warthogs out of my 30.06. Thinking about it my zero stop on the scope on that rifle is still "zerod" for the 125s.

 

[DumpHollow]

Why would anyone resort to using 4000 fps .30 cal projectiles to obliterate a prairie dog town when there are much better thermobaric or plutonium-based alternatives?

The first question that I have about this topic is, "How do you get PD precision unless you have built a rifle with an appropriate twist?" Having hunted them, they are small targets.

 

[moorepower]

The first question that I have about this topic is, "How do you get PD precision unless you have built a rifle with an appropriate twist?" Having hunted them, they are small targets.

Not sure how accurate it is, but it would be fun to watch. I am actually thinking about a slow twist 7mm barrel for a .284 shooting 100 grain hp at 35-3600.

 

[Ray123]

I don't shoot light bullets in anything serious, because they slooow down sooo fast, and wind drift at longer ranges wild, and end up with little energy on the target.
That said,... want Fast?...the 17 Remington will hit 4870 fps with the 15.5 gr NTX copper bullet from Hornady chronographed with the powder I had, but the loading manual says they will top out at 4920 fps with a powder I didn't have. Approaching 5000 fps the fastest bullet ever over my chronograph. There are light bullets from Lehigh Defense 308 Close Quarters 78 gr and run them in large cases...I've only used them in the 300 blkout and 300 hamr. Also shoot 9mm in ar 15 at 2498 fps...200 gr SMK 2673 from an 18" AR10...So I always push the speed limit but not with light bullets ...mostly heavy bullets like a 308 230 ATip at 2620 fps from a 308 a Win, with a 30" barrel.

 

[Ned Ludd]

Hornady has now the CX line of bullets
Here is their 0.308 110gr projectile

A bonus with mono bullets is that fly down the barrel faster due to less friction. Thus, a 110gr mono bullet can gain an extra 150 fps at the MV from 30' barrel, or 4150fps.
In a 26" barrel, 4000fps

https://www.hornady.com/bullets/rifle/30-cal-.308-110-gr-cx#!/

I've loaded many monolithic copper solids for a .308 Win F-TR rifle. I did not observe any significant increase in velocity, or decrease in pressure due to lesser friction. They behaved much like lead core bullets in terms of reasonably achievable velocity/pressure in my hands.

There are also other considerations that are important in terms of getting the copper monolithics to shoot well. Because they are generally much longer than a lead core bullet of comparable weight, a sufficiently fast twist rate is necessary to stabilize them. In the case of the monolithics I've used, the nose region also tends to be quite long relative to comparable weight lead core bullets, and the "bearing surface length" (i.e. drive bands) is often much shorter. Thus, having the rifle chambered/throated with the appropriate freebore is also a consideration. Finally, it is of note that many F-TR shooters have tried the monolithic solids, likely lured by the extraordinarily high BCs associated with some of them. To the best of my knowledge, few, if any, are actually using them in competition. The primary reason for this is typically unexplained and unacceptable vertical dispersion. No one that I know of has been able to successfully resolve this issue and obtain acceptable precision for F-TR shooting.

In the case of the lighter (100-120 gr) monolithics such as Hornady's 110 CX bullet, it may be that some of these considerations such as barrel twist and freebore length are not an issue as a rifle chambered for bullets up to the 168-175 gr range might be perfectly suitable. One really needs to have the projectiles in hand to measure in the rifle, or at least have an accurate set of bullet dimensions. Assuming the rifle is already set up suitably for the monolithic bullet dimensions, one can then run some test loads to determine whether they provide the necessary precision for the desired type of shooting.

To be clear, I'm not in any way attempting to talk you out of trying these bullets. However, having had a rifle custom-built to use monolithic solids in F-TR and been pretty disappointed with the results, I think it's only fair to caution others that the monolithics don't always behave like their comparable weight lead core counterparts. If the rifle setup is amenable to the dimensions of this particular bullet, then you're already ahead of the curve in that you won't end up with a chamber and twist rate that is poorly suited to existing lead core bullet alternatives. In that scenario, a single box of bullets would likely be sufficient to determine how well they shoot, which is a pretty minor expense in the grand scheme of things.

 

[Darwin]

The first question that I have about this topic is, "How do you get PD precision unless you have built a rifle with an appropriate twist?" Having hunted them, they are small targets.

I’ve never hunted them. 1/9 with 110’s at 3940.
Is the 4 good enough if it was centred?

 

[DumpHollow]

I’ve never hunted them. 1/9 with 110’s at 3940.
Is the 4 good enough if it was centred?
View attachment 1348706

The 4 shots are nice, and they would work. But, does the flier indicate the true precision of your load? You have an 80% confidence level of vaporization out to a couple hundred yards. PD's are fun targets.

 

[wboggs]

I've loaded many monolithic copper solids for a .308 Win F-TR rifle. I did not observe any significant increase in velocity, or decrease in pressure due to lesser friction. They behaved much like lead core bullets in terms of reasonably achievable velocity/pressure in my hands.

There are also other considerations that are important in terms of getting the copper monolithics to shoot well. Because they are generally much longer than a lead core bullet of comparable weight, a sufficiently fast twist rate is necessary to stabilize them. In the case of the monolithics I've used, the nose region also tends to be quite long relative to comparable weight lead core bullets, and the "bearing surface length" (i.e. drive bands) is often much shorter. Thus, having the rifle chambered/throated with the appropriate freebore is also a consideration. Finally, it is of note that many F-TR shooters have tried the monolithic solids, likely lured by the extraordinarily high BCs associated with some of them. To the best of my knowledge, few, if any, are actually using them in competition. The primary reason for this is typically unexplained and unacceptable vertical dispersion. No one that I know of has been able to successfully resolve this issue and obtain acceptable precision for F-TR shooting.

In the case of the lighter (100-120 gr) monolithics such as Hornady's 110 CX bullet, it may be that some of these considerations such as barrel twist and freebore length are not an issue as a rifle chambered for bullets up to the 168-175 gr range might be perfectly suitable. One really needs to have the projectiles in hand to measure in the rifle, or at least have an accurate set of bullet dimensions. Assuming the rifle is already set up suitably for the monolithic bullet dimensions, one can then run some test loads to determine whether they provide the necessary precision for the desired type of shooting.

To be clear, I'm not in any way attempting to talk you out of trying these bullets. However, having had a rifle custom-built to use monolithic solids in F-TR and been pretty disappointed with the results, I think it's only fair to caution others that the monolithics don't always behave like their comparable weight lead core counterparts. If the rifle setup is amenable to the dimensions of this particular bullet, then you're already ahead of the curve in that you won't end up with a chamber and twist rate that is poorly suited to existing lead core bullet alternatives. In that scenario, a single box of bullets would likely be sufficient to determine how well they shoot, which is a pretty minor expense in the grand scheme of thi

I've loaded many monolithic copper solids for a .308 Win F-TR rifle. I did not observe any significant increase in velocity, or decrease in pressure due to lesser friction. They behaved much like lead core bullets in terms of reasonably achievable velocity/pressure in my hands.

There are also other considerations that are important in terms of getting the copper monolithics to shoot well. Because they are generally much longer than a lead core bullet of comparable weight, a sufficiently fast twist rate is necessary to stabilize them. In the case of the monolithics I've used, the nose region also tends to be quite long relative to comparable weight lead core bullets, and the "bearing surface length" (i.e. drive bands) is often much shorter. Thus, having the rifle chambered/throated with the appropriate freebore is also a consideration. Finally, it is of note that many F-TR shooters have tried the monolithic solids, likely lured by the extraordinarily high BCs associated with some of them. To the best of my knowledge, few, if any, are actually using them in competition. The primary reason for this is typically unexplained and unacceptable vertical dispersion. No one that I know of has been able to successfully resolve this issue and obtain acceptable precision for F-TR shooting.

In the case of the lighter (100-120 gr) monolithics such as Hornady's 110 CX bullet, it may be that some of these considerations such as barrel twist and freebore length are not an issue as a rifle chambered for bullets up to the 168-175 gr range might be perfectly suitable. One really needs to have the projectiles in hand to measure in the rifle, or at least have an accurate set of bullet dimensions. Assuming the rifle is already set up suitably for the monolithic bullet dimensions, one can then run some test loads to determine whether they provide the necessary precision for the desired type of shooting.

To be clear, I'm not in any way attempting to talk you out of trying these bullets. However, having had a rifle custom-built to use monolithic solids in F-TR and been pretty disappointed with the results, I think it's only fair to caution others that the monolithics don't always behave like their comparable weight lead core counterparts. If the rifle setup is amenable to the dimensions of this particular bullet, then you're already ahead of the curve in that you won't end up with a chamber and twist rate that is poorly suited to existing lead core bullet alternatives. In that scenario, a single box of bullets would likely be sufficient to determine how well they shoot, which is a pretty minor expense in the grand scheme of things.

Ned
That is a very thorough summary of monos for precision shooting. I continue to believe their best use is in hunting where penetration is needed or high velocity/ fast twist will cause cup and core bullet failure. They generally are very accurate with 0.5" groups often achieved.
Thanks for your insights.
Bill

 

[FNSafari]

I've loaded many monolithic copper solids for a .308 Win F-TR rifle. I did not observe any significant increase in velocity, or decrease in pressure due to lesser friction. They behaved much like lead core bullets in terms of reasonably achievable velocity/pressure in my hands.

There are also other considerations that are important in terms of getting the copper monolithics to shoot well. Because they are generally much longer than a lead core bullet of comparable weight, a sufficiently fast twist rate is necessary to stabilize them. In the case of the monolithics I've used, the nose region also tends to be quite long relative to comparable weight lead core bullets, and the "bearing surface length" (i.e. drive bands) is often much shorter. Thus, having the rifle chambered/throated with the appropriate freebore is also a consideration. Finally, it is of note that many F-TR shooters have tried the monolithic solids, likely lured by the extraordinarily high BCs associated with some of them. To the best of my knowledge, few, if any, are actually using them in competition. The primary reason for this is typically unexplained and unacceptable vertical dispersion. No one that I know of has been able to successfully resolve this issue and obtain acceptable precision for F-TR shooting.

In the case of the lighter (100-120 gr) monolithics such as Hornady's 110 CX bullet, it may be that some of these considerations such as barrel twist and freebore length are not an issue as a rifle chambered for bullets up to the 168-175 gr range might be perfectly suitable. One really needs to have the projectiles in hand to measure in the rifle, or at least have an accurate set of bullet dimensions. Assuming the rifle is already set up suitably for the monolithic bullet dimensions, one can then run some test loads to determine whether they provide the necessary precision for the desired type of shooting.

To be clear, I'm not in any way attempting to talk you out of trying these bullets. However, having had a rifle custom-built to use monolithic solids in F-TR and been pretty disappointed with the results, I think it's only fair to caution others that the monolithics don't always behave like their comparable weight lead core counterparts. If the rifle setup is amenable to the dimensions of this particular bullet, then you're already ahead of the curve in that you won't end up with a chamber and twist rate that is poorly suited to existing lead core bullet alternatives. In that scenario, a single box of bullets would likely be sufficient to determine how well they shoot, which is a pretty minor expense in the grand scheme of things.

Ned, has anyone you know sorted mono solids based on a full caliber point on the bullet? I don't shoot F class hence I have no idea into how much loading detail most shooters go. Tks --Greg

 

[Ned Ludd]

Ned, has anyone you know sorted mono solids based on a full caliber point on the bullet? I don't shoot F class hence I have no idea into how much loading detail most shooters go. Tks --Greg

I'm not exactly sure what you mean by "sorted mono solids based on a full caliber point on the bullet". Can you elaborate?

The monolithic solids I have used were all CNC machined, no sorting was necessary or needed, as the bullet dimensions within a single Lot# were ridiculously uniform. I'm sure there can be some subtle differences between different monolithic solids, especially between the target and hunting bullet types. However, the need for a faster twist barrel and shorter freebore is probably close to "universal", because AFAIK they all have a shorter bearing surface (drive bands) and are longer than lead-core bullets of the same weight class due to being made of copper, gilding metal, or some similar alloy that is far less dense than lead.

 

[FNSafari]

I'm not exactly sure what you mean by "sorted mono solids based on a full caliber point on the bullet". Can you elaborate?

The monolithic solids I have used were all CNC machined, no sorting was necessary or needed, as the bullet dimensions within a single Lot# were ridiculously uniform. I'm sure there can be some subtle differences between different monolithic solids, especially between the target and hunting bullet types. However, the need for a faster twist barrel and shorter freebore is probably close to "universal", because AFAIK they all have a shorter bearing surface (drive bands) and are longer than lead-core bullets of the same weight class due to being made of copper, gilding metal, or some similar alloy that is far less dense than lead.

What I mean is, sorting bullets with a gauge that comes to rest on the bullet where it first becomes, lets say, .308".

 

[Ned Ludd]

What I mean is, sorting bullets with a gauge that comes to rest on the bullet where it first becomes, lets say, .308".

I see, you are referring to length sorting the monolithics. FWIW - I have loaded three different monolithics by two different manufacturers. All three were target bullets, and CNC-machined. I literally could not detect length differences in the different regions of the bullets using typical Mitutoyo calipers with .0005" readability, and trying to sort them by length would have been fruitless. Thus, the CNC machine tolerances for the bullets I have used were extremely good. In fairness, there are a lot of other monolithics out there these days, so I don't know whether they are all machined to such tight tolerances. If not, some form of length sorting may be of benefit. One could readily determine this by measuring the length of the various segments for a small number of bullets, to see whether sufficient length variance existed to warrant sorting them.