How low is too low and why ?

[zzt]

I tried really low loads and didn't like the way they operated the gun, or performed.  115s at 109 PF and 120 PF feel pretty much the same and work well.  124s at 124 PF actually feel a bit softer, probably because the recoil is not a s sharp as with the 115s.  I'm going to try some 147s just to see if they make any difference.

 

My bolt, 5.56 spring and Blitkrieg buffer weigh 22 ox., so most of the recoil is the bolt slamming back and forth.  I'm trying to find a load that produces the most stable dot.  Believe it or not, some of the faster loads have less dot bounce/wiggle than the softer ones.

[zzt]

BTW, I meant to mention this earlier, but N310 is absolutely horrible for consistency at anything under max loads.  It is also horribly temperature sensitive.  So any loads you work up now are going to be a lot hotter in the Summer.

 

If you want a fast powder with no pressure spikes and no discernible temperature sensitivity, try Alliant e3.  It is spectacular.

[tomv]

My friend started shooting Atlanta Arms Steel Challenge ammo in his Open gun a couple of years ago. Up to that point I was shooting Montana Gold 115gr JHP over 3.8 gr of N320  in my Steelcats. ( BTW, a very good PCC load, about 109 PF in a 5" barrel.) I took some of the Atlanta apart and identified the bullet as a Berry's 100 gr hollow base  9mm profile set at 1.1"and the powder as  VV N310. 3.9 gr. Power factor for this stuff runs at 112 to 118 over my chrono. I decided to use the Montana gold 95 gr JHP to try to duplicate the load and ended up at 4.0 gr of N310 with bullet set at 1.085". This runs at 112 +- PF and cycles my open gun a little faster than the 115/N320 load. It will run in some guns where the N320 will not, probably due to the higher impulse of faster powder. This has proved to be an accurate and reliable load for a couple of years now in temperatures ranging from the 40's to 90's.

 

The MG 95 JHP load wouldn't feed in my PCC so I replaced it with the Berry's 100 gr HB which feeds just fine. Don't exactly recall why I started to experiment with lower powder charges because the 3.8 gr load I started with felt fine to me, It was probably jrdoran's fault . Once on that slippery slope I kept reducing charge weight a couple of tenths at a time until I got the gun to fail at 2.2gr. It ran just fine at 2.5gr with positive cycling and brass ejection, which was amazing to me. I'm in CT so the temperature was around 40F during the testing.  My PCC ises a Taccom shrouded barrel, JP bolt and JP SCS buffer with 3 steel and 1 tungsten weight with a green spring.

 

I took samples of the different loads I tried and shot groups from a rest at 17 yards and found the sweet spot at 2.8 gr with groups of about an inch. Maybe an anomaly, but higer and lower charge weights were about double that. I've since verified accuracy at 2.8gr. I think the short distances we shoot Steel Challenge at somewhat mitigates the effects of the high velocity variance we are seeing with the light loads. I agree that 2" groups are terrible but I think they are acceptable for SC given the fact that we never see fliers.

 

For reference, the Atlanta 100 gr SC load we started with has a SD of 12 to 15 fps on my chrono. My 95 gr MG load is about the same. At this point I haven't tested my load with Berry's bullet and 3.8 gr of N310 but I suspect it will be in the same range.

 

 

[Absocold]

Second the Alliant E3 suggestion. I have no idea why that powder is so soft. It's made from feathers and clouds I think.

 

When you're making mouse fart loads, it's safer to use a fluffy powder that fills up the case more and a lighter bullet than the other way around. Prevents detonations and possible double (or triple) charges.

 

High order detonations from low powder volume aren't so much of an issue with the short 9mm case, it's something that happens with longer rounds like 38SPL and such. Even then it's still pretty rare. However you do get uneven burn rates when the powder volume vs case capacity is too low, no matter your caliber.

 

I've made 280 fps loads for 38/357 and 3,000 fps loads for 45ACP. Experimenting is fun but mind your safety issues way harder than usual when you step outside the norm.

[Shorty4087]

A friend of mine is running very low as well for Steel Challenge and has already blown up one BSF barrel and recently had a squib this past match, which could’ve lead to a second barrel. Running on the ragged edge has its potential rewards, but the risks are there as well...

[usmc1974]

I was just wondering, have you tried Trail Boss? It it makes cowboy action shooter loads so soft and quiet you can't even hear them. Cycling the action on the 73 rifle makes more noise, then the round going off you have to wait to hear it hit the steel. 90 year old. Cowboy female shooters use it to make flea fart loads.

Edited February 28, 2020 by usmc1974

[tomv]

1 hour ago, usmc1974 said:

I was just wondering, have you tried Trail Boss? It it makes cowboy action shooter loads so soft and quiet you can't even hear them. Cycling the action on the 73 rifle makes more noise, then the round going off you have to wait to hear it hit the steel. 90 year old. Cowboy female shooters use it to make flea fart loads.

What caliber and bullet weight are the cowboy shooters using?

[usmc1974]

8 minutes ago, tomv said:

What caliber and bullet weight are the cowboy shooters using?

A lot of them that shoot 38 used like a 95 grain bullet and 2 grains of powder with a magnum primer. This is the whole purpose behind trail boss. To make safe flea fart loads. I hope this helps stay safe.

[tomv]

I'm actually using more powder than that already  in a smaller case. Don't understand why the load you cited would be any safer.

[tomv]

I was on the Wiland website today and noticed that they are advertising the ability of their barrel, bolt and buffer combination to shoot 80 PF ammo. Does anyone know the load data to which they are referring?

[MemphisMechanic]

On 2/28/2020 at 1:29 PM, tomv said:

I'm actually using more powder than that already  in a smaller case. Don't understand why the load you cited would be any safer.

Density is the factor you’re forgetting. For example, 3.0 grains of titegroup takes up FAR less case volume than 3.0 grains of Prima V. You can double-charge with titegroup and still have plenty room to seat a bullet if you’re not paying attention. With Prima V or clays, half of the second charge will have spilled all over your press and make it pretty hard to miss the overflowing mound of powder.
 

A light, fluffy powder will take up far more case volume at low charge weights - and therefore burn more consistenly. This would reduce your chances of a squib, and shrink your SDs.

 

The theory goes: When you have almost no powder in the case, you get a very different burn if it’s all piled up at the flash hole and burns back-to-front the way it ought to... versus when it’s spread out along the bottom of the case and all ignites more or less at once as the flame from the primer passes above it.

 

Edited March 4, 2020 by MemphisMechanic

[tomv]

MM, thanks for the input. I agree with everything you have said.  I've been reloading  for about 40 years now and your comments are fundamental considerations for doing this safely.

 

I'm not familiar with Prima V but from what I've just learned, it's a very high density powder which performs close to VV N320. I've used a lot of Clays over the years and it is lower density than either of the VV powders but is  notoriously hard to meter, especially at low charge weights.

I use a lot of n31 and N320 in my Open Steel Challenge loads. The N310 with a MG 95 gr JHP and the N320 with MG 115gr JHP. They are both about 110 PF. The N310 load cycles the slide faster (in a 5" Limcat Steelcat) and will run in almost everything I've tried it in. The 320 load feels softer and won't run in typical bull barrel guns. The light mass of the bushing barrel Steelcat makes it possible to run  this load successfully.

 

This is the basis for using N310 powder for this light load experimentation. Probably not the most scientific approach, but based on my experience, the fast burn rate and subsequent high impulse of the N310  gets things moving with light bullets / low powder charges. My guess is that with slower powders there will be a minimum charge weight which allows the gun to cycle that produces a velocity which is higher than I can get with a faster powder. I guess I'm going to have to try this to find out. Good thing I'm retired! :-).

 

As a practical matter, I like the way my PCC runs at 90 PF and will probable stay there. At that velocity ejected cases are clean, indicating that pressure is sufficient to seal in the chamber. While Std Dev is high at 41 fps I'm not concerned with squibs because a 2 sigma velocity variation from the mean would still result in a velocity greater than 800 fps. I am playing with seating the bullet deeper in the case to reduce case volume to see if that reduces the Std Dev, but seating the bullet deeper could itself  have an adverse impact on accuracy because of bullet jump from case to rifling.

 

I'm also not concerned with double charges. I'm loading on a Dillon 1050 with Mark 7 drive and think it's nearly impossible to get a double charge with that setup. However, still need to be careful.

 

I hope I'm not coming across as defensive, I really do appreciate the input.

 

 

 

 

 

 

[HesedTech]

I'm not sure why the OP is asking this question, except maybe because it's fun to experiment and to see what can be accomplished.

 

How low and why? Hmmm

 

If PF is not a requirement I would think there are only two major hurdles:

 

1. The ammo has to have enough bang to operate the gun
2. The ammo has to have acceptable accuracy at the distances desired to shoot.

 

I think it's that simple.

 

As in all things, be careful and safe.

 

Good luck in your endeavor.

 

Oh, I forgot to mention price. Maybe part of your quest could also be trying to achieve the above at the lowest possible price. 

Think:

Bullets

Powder

Brass

Primers

 

Using the lowest possible priced versions of the above can you achieve your quest? 

Edited March 5, 2020 by HesedTech

[jrdoran]

Just an update.  I am successfully shooting 62PF with Ruger ( 5" barrel ) ( stock action & receiver ) ;     95gr Montana Gold;   2.4gr N310;     

Have had zero failures in 500+ rounds.   Do appreciate all the information and points of view.  I've been cautiously experimenting up/down the PF scale.   Don't want to risk a squib. 

 

Have gotten good accuracy with the above load.  The 100gr Berry's were less accurate until we got them above 100PF with enough velocity.