Muzzle flash

[zzr600]

I use Hodgdon H335 in a 16" barrelled .308 and I have worked up an accurate load. A reasonable amount of muzzle flash doesn't bother me but suggests incomplete burning of the propellant. Is this the case? Would a slightly faster powder be better? I need to change from H335 as it's on the banned list now, and some have suggested Ramshot Tac or N140, but both appear to be slower burning propellants on the chart's I've seen.

N133 is a slight slower powder than H335 but bizarrely VihtaVuori only list reloading charges for a 165gn bullet but not the 168gn I currently use. I presume a 3gn difference in bullet weight is hardly going to affect the amount of powder used?

 

[devonair]

I use Hodgdon H335 in a 16" barrelled .308 and I have worked up an accurate load. A reasonable amount of muzzle flash doesn't bother me but suggests incomplete burning of the propellant. Is this the case? Would a slightly faster powder be better? I need to change from H335 as it's on the banned list now, and some have suggested Ramshot Tac or N140, but both appear to be slower burning propellants on the chart's I've seen.

N133 is a slight slower powder than H335 but bizarrely VihtaVuori only list reloading charges for a 165gn bullet but not the 168gn I currently use. I presume a 3gn difference in bullet weight is hardly going to affect the amount of powder used?

Lyman data; hope this is of some help.....
That's a mighty short barrel, surely you require a faster powder? Please correct me if I'm wrong

 

[devonair]

Lyman burn rate chart;

Hope this helps ( N150 is no 73 on list, much slower)

 

[devonair]

Lyman burn rate chart;

Hope this helps ( N150 is no 73 on list, much slower)

N140 is #68 on my burn rate chart.

 

[zzr600]

Lyman data; hope this is of some help.....
That's a mighty short barrel, surely you require a faster powder? Please correct me if I'm wrong

Sorry, yes I meant a faster powder such as N133 so that all the powder is burned

 

[Flash9919]

What charge are you currently using?...... I'll run it through QL later…..but with that barrel length there won't be too many options that will burn at 100% without loosing a fair bit of velocity....Also does 16" include the chamber??

 

[Sinistral]

Sorry, yes I meant a faster powder such as N133 so that all the powder is burned

 

[Sinistral]

Sorry, yes I meant a faster powder such as N133 so that all the powder is burned

Err … I know someone who has shortened his .308 barrel to 16” (against advice) who is is using Viht N133 with 150gr. Vihtavuori only recommend this for lightweight bullets of 125gr.

I use N135 for 125gr - 130gr as it’s in their loading tables.

I don’t find it at all bizarre that their test results recommend slower Vit powders for heavier bullets. Their data shows N133 is quite a bit faster than H335 when it’s actually tested. Burn rates vary in every manual so they are of only general use. Here’s some reliable data:-

http://www.6mmbr.citymaker.com/f/Sierra308Win.pdf

 

[zzr600]

What charge are you currently using?...... I'll run it through QL later…..but with that barrel length there won't be too many options that will burn at 100% without loosing a fair bit of velocity....Also does 16" include the chamber??

40 grains H335 for 168 gn Sierra HPBT. 16" I thinks is just the barrel length

 

[Flash9919]

Don't take it as gospel but that should get you about 98% burn in your barrel with that load.....have you tried stepping up the charge weight to increase the burn....I reckon you've got at least 2 grains to play with maybe a touch more...N133 or 135 will get you to 100% but I'd be inclined to go to a slightly slower powder and increase the charge weight...maybe viht 140

 

[royr]

308 REM- 16" barrel - 168 Sierra HPBT - - Form Fired Case fill of 49.5cc with COAL of 2.800" - bullet seated to 0.429" SAMMI MAX pressure 62000psi
With the Current Load QL Pridicts:-
Hodgdon H355 40gns - 80.3% case fill -predicted velocity 2286ps - powder burnt in 16" barrel 98% - predicted pressure 44076psi 27% UNDER MAX
If reworking this load:-
Hodgdon H355 42.95gns - 86.2% case fill -predicted velocity 2444fps - powder burnt in 16" barrel 99.42% - predicted pressure 54000psi 10% UNDER MAX


Searching for 95% burn of propellant in 16" barrel, with REACH Compliant powders:-
ReloadSwiss 46.79gns - 100% case fill -predicted velocity 2510fps - powder burnt in 16" barrel 98.1% - predicted pressure 54000psi 10% UNDER MAX
Hodgdon CFE223 48.95gns - 99% case fill -predicted velocity 2496ps - powder burnt in 16" barrel 94.7% - predicted pressure 54000psi 10% UNDER MAX
Ramshot Big Game 47.77gns - 99% case fill -predicted velocity 2490ps - powder burnt in 16" barrel 96.% - predicted pressure 54000psi 10% UNDER MAX
Norma 203B *C 45.09gns - 99% case fill -predicted velocity 2470fpss - powder burnt in 16" barrel 96.4% - predicted pressure 54000psi 10% UNDER MAX
Vihtavuori N540*C 45.07gns - 98% case fill -predicted velocity 2445fps - powder burnt in 16" barrel 99.3% - predicted pressure 54000psi 10% UNDER MAX
Norma 202*C 42.8gns - 96% case fill -predicted velocity 2442s - powder burnt in 16" barrel 99.4% - predicted pressure 54000psi 10% UNDER MAX
Vihtavouri N140 *C 43.6gns - 98% case fill -predicted velocity 2424fps - powder burnt in 16" barrel 99.6% - predicted pressure 54000psi 10% UNDER MAX
Vihtavouri N133 *C 40.5gns - 97% case fill -predicted velocity 2380ps - powder burnt in 13.7" barrel 100% - predicted pressure 54000psi 10% UNDER MAX

NB. Always work up to these figures looking for any over pressure signs!

Hope this guide assists in your final choice.
Regards
RoyR
PS. just an observation when Chronoing Vihtavouri powders, they are always higher FPS than predicted.

 

[royr]

Ist Line omission of powder number:-
ReloadSwiss RS 52 - 46.79gns - 100% case fill -predicted velocity 2510fps - powder burnt in 16" barrel 98.1% - predicted pressure 54000psi 10% UNDER MAX

 

[zzr600]

308 REM- 16" barrel - 168 Sierra HPBT - - Form Fired Case fill of 49.5cc with COAL of 2.800" - bullet seated to 0.429" SAMMI MAX pressure 62000psi
With the Current Load QL Pridicts:-
Hodgdon H355 40gns - 80.3% case fill -predicted velocity 2286ps - powder burnt in 16" barrel 98% - predicted pressure 44076psi 27% UNDER MAX
If reworking this load:-
Hodgdon H355 42.95gns - 86.2% case fill -predicted velocity 2444fps - powder burnt in 16" barrel 99.42% - predicted pressure 54000psi 10% UNDER MAX


Hope this guide assists in your final choice.
Regards
RoyR
PS. just an observation when Chronoing Vihtavouri powders, they are always higher FPS than predicted.

Thanks a bunch for that. What software do you use and how accurate is it?

 

[Flash9919]

That's Quickload data and it's pretty accurate. That said any variation in case capacity, seating depth, powder burn rate etc can have a big effect on pressures so as has already been suggested work up to top loads. As a general rule if the input data into QL is accurate then the output data is pretty close. In my 7x64 and 9.3x62 it's spot on, in 300wm I normally find velocities to be above predicted values regardless of powder used.

 

[royr]

Hello ZZR600,
JMS Arms - QuickLoad/QuickTarget CD software @ UK. £125.
Initially it may appear an expensive purchase, but I've 3 Manufactures Reloading Manuals that cost nearly that amount and these don't give me 10% of the information I require when researching information for a new load.
You can input so many variables into the program, bullet type & brand, powder choices, different bullet seating depths, powder % burn rate in a any given length barrel, MAX PSI pressure e.t.c, e.t.c, and get a pretty good approximation of the finished product. I would estimate accurate to within 5% of predictions. Usually any errors have been the result of same case (BRASS) manufacturing tolerances.
There are YouTube Videos on this.
Regards
RoyR

 

[royr]

I would add:-
Criteria for Fox control a night; I wanted a complete 100% powder burn in my Tikka T3 20" barrel so there is NO MUZZEL FLASH - very important, especially so when a vixen emerges with 5 or 6 cubs in tow.
Dispatch the vixen first, followed by the cubs in disarray - in the past, muzzel flash with Factory Ammo caused them to scatter, hence I started reloading using QL for NO muzzle flash. And the moderator does not get fouled up with unburnt powder.
Regards
RoyR