Retmbo residue ?!?

[tbrice23]

I clean relgiously after every range session, especially if I'll be switching to a different powder for the next range session.
I think its miraculous how I get a perfect molding of my groves after using 50% 50% kroil hoppes benchrest .
NO OTHER POWDER gives me this effect. I can almost measure the width of my groves with these strips.
These pics are after Shooting 20-25 rounds 70.9 to 73.2 grains in 24" barrel. Has anyone else seen this effect from Retumbo?

 

[Pa Grizz]

I have been using it out of three of my guns and I asked a couple of my friends that uses it and nobody has seen that before.I have no idea what would cause the residue to come out like that.

 

[tbrice23]

Its obvious through my borescope that It's all gone when im done.
There's no over pressure at the high charge. Accuracy is ok at 225 yards.
Even so I'm almost thinking it's unburned retumbo????

 

[thekyrifleman]

I see similar results with my 7stw, RL25, 160 AB. IMO, it is the solvent mixture. I use Shooters Choice/Kroil 50/50. Kroil really seems to get down under the residue.

 

[tbrice23]

It must be the mixture, slow powder and a mirror smooth bore.

 

[westcliffe01]

OK, you don't provide all the specifics, but I'm assuming a 300WM ? I see 168gr on the target and ~70gr of powder ?

So if this is a 300WM shooting a 168gr bullet, then peak velocity would be attained with 4350 or 4831. These powders are listed at positions 114 and 125 on the powder burn rate chart. Retumbo comes in at 138 and the last position is 145 (VihtaVuori 20N29). Now H1000 is not far from peak velocity, but it takes 84gr of H1000 vs 70gr of 4350. No doubt H1000 would leave a lot of residue too under such circumstances.

If you would go up to a much heavier bullet, then Retumbo would be a more suitable powder although still not the best. Its just too slow.

 

[tbrice23]

The load is listed on the target.
7mm Remington magnum
168 vldh
Retumbo
Gm215m

 

[tbrice23]

OK, you don't provide all the specifics, but I'm assuming a 300WM ? I see 168gr on the target and ~70gr of powder ?

So if this is a 300WM shooting a 168gr bullet, then peak velocity would be attained with 4350 or 4831. These powders are listed at positions 114 and 125 on the powder burn rate chart. Retumbo comes in at 138 and the last position is 145 (VihtaVuori 20N29). Now H1000 is not far from peak velocity, but it takes 84gr of H1000 vs 70gr of 4350. No doubt H1000 would leave a lot of residue too under such circumstances.

If you would go up to a much heavier bullet, then Retumbo would be a more suitable powder although still not the best. Its just too slow.

Yes BUT I've got to say that h1000 in MY 300wm and 180bt up to 82 grains burns super clean. Don't know if you can tell by the pic but the paper is still pretty white in the bullet hole.

 

[westcliffe01]

OK 7 Rem Mag. Retumbo is listed in the recommended powders, but you get the same results with 10gr less H4831 and 16gr less H100V. I have personally found availability of H100V to be quite good and it has been producing better velocity for me in my 243 AI than any other powder I have tried.

Its probably a good powder for barrel life, but otherwise not the best choice. Less than 100 rounds per pound and needing to use nearly 26% more powder per load to achieve equal results ?

On the other hand, we all know how hard it has been to get your hands on your favorite powder for the last 15 months or so....

 

[tbrice23]

This barrel finds happiness at some velocity with 4 powders so far. (Except rl22 dammit). H1000 is its steady diet. I just love that 3160 fps reading and with no pressure signs with Retumbo. H1000 can't do that. It just makes me very cautious when strips of material unscrews from my barrel.

 

[westcliffe01]

H100V has a modified pressure curve (less of a spike) so you might want to try it.

 

[tbrice23]

Is it extruded or ball or what? Its not a temp
Insensitive (extreme) powder on their site.

 

[westcliffe01]

Its listed under spherical powders:

H100V
This powder is the result of combining the technologies of spherical powders and extruded propellants. The chemistry of a spherical powder is combined with the geometry of an extruded propellant, creating a smooth-metering, super short granule extruded shaped propellant with high energy. HYBRID 100V has a burn speed between H4350 and H4831, yielding superb performance in such popular calibers as 270 Winchester, 243 Winchester Super Short Magnum, 7mm Remington Magnum, 300 Winchester Magnum and dozens more.
Sperical Rifle Powders

 

[sendero72]

Your tightest group is with 70.9 grs. How clean is the barrel with this load? Adding 2 grains at 72.9, I don't think you're burning all the powder and the group is much larger. I'll take accuracy over speed any day. You can also try a 210 primer and may get a more even burn rate. Just my .02