Home Forums Hunting & Shooting Ask The Gunwriters Reloader 17 question...

I am wondering because Rl-17 has an impregnated retardent and therefore doesn't initially have a pressure spike can we depend on tradition signs of pressure like sticky , stiff bolt openings? I am wondering if part of the reason we are seeing better velocity is because we are just using more powder than we should and because the traditional signs of pressure are not present we think we are OK? In my feeble mind it takes X amount of pressure to push a given bullet to a certain velocity, there is no majic or free lunch. Are we taking more chances than we should thinking we are OK or safe? I don't know the answer to this question but it along with some others, ( mostly about female logic) have been circling around in my brain. I know there are some very gifted analytical minds on this board so I thought I would ask. The questions about female logic I have come to believe are with out answer and I have come to believe are the price of admission to achieve a happy relationship.
Buckfever1

If RL-17 is anything like the powders used in the new Hornady Superformance stuff (which I am sure it is) then their is a bunch of good reading out there for you to figure it out.

All I know is that I've looked the Alliant data over carefully and there isn't any magic 100+ fps gain in any cartridge with RL-17, as so many handloaders have been reporting. And so far Alliant's is the only pressure-tested data out there.

In fact, the only "magic powder" that's recently appeared in powder-company loading data is Hodgdon Hybrid 100V, which does show a very significant gain in velocity with certain cartridge/bullet combinations. Yet we hear a lot more about RL-17....

I'll also comment that the absence of traditional "pressure signs" such as primer appearance, bolt lift, etc. doesn't mean much. With some of today's components and rifles such signs often don't show up until the pressure is at least 70,000 psi or even higher.

There wasn't a lot of published data when I started loading with RL-17. A chronograph told me when my loads were too hot. Absent were sticky bolt lift and flattend primers...but muzzle velocity became very erratic.

I backed off till I had consistant velocities (270 WSM).About the same velocity as factory ammo with better accuracy.

Dan (not a gun writer)

This isn't a very technical response to what can be a great informative thread, but I have loaded with RL-17 ( 1lb worth ) in a few catridges, and saw no real velocity gain at seemingly safe pressure and in my limited use it was not as accurate as other proven loads.
The exception was in a .30'06 target rifle where I saw nearly 100fps over its previous top end load, but again not as accurate. 2745fps with a 210gr Berger in a 24" barreled .30'06 is attractive but didn't shoot all so well at extended range.

If you put enough of it in you will get traditional pressure signs. Trust me!

A lot of the guys that I shoot with are using it to replace H4350 and seemingly getting more velocity than they could get with H4350. It also seems to burn a little cleaner. I am using it in the .300 WSM with 200gr. bullets and the 6X47 Lapua with 108's. Good accuracy and velocity in both.

Lefty C

I got a genuine 50-60 fps gain in my last 300 WSM over H4350 with 180's. Not monumental by any means, but the gain was there.

Today with the 270 Win at the range, I ran 150 Partitions with Alliants top load of 51.5 gr's... this load was about 70 fps behind 58.0 gr's H4831sc. I believe I could go to 52.0 gr's RL17 in my rifle, but velocity will still fall behind 58.0 of H4831 which runs 2,840-ish.

Of course accuracy is more important than 50 fps...

What I wonder is if the delayed powder burn actually moves more pressure down the barrel to thinner barrel walls that are not designed to withstand it. Maybe it does not show up at the bolt but close to the muzzle.

Well, this is anecdotal and the famous example of one, but in a SA 700 and a OAL of 2.95" my 284 hit 3150fps with R 17 and the very long 140-gr TTSX (1.3"). This was a "stable" load with no primer flattening, case sticking, stiff or frozen bolts and was a 150fps over H4350 when I did reach some of these traditional high pressuren signs.

Not intending it to be a 7mm Rem mag I backed down to 3050fps which is plenty for it's anticipated use as I decided that velocity, within the context of historical known performance parameters, was indicating that pressures were much higher than otherwise indicated.

6mmBR.com has a great thread on RL-17. Bob Jensen and German Salazar are some pretty savy riflemen. They used a strain gauge for their results. http://www.6mmbr.com/reloder17.html

Their article inspired me to try RL-17. A 6mm rem, and a 284 Win showed stunning velocity gains with excellent accuracy. There were more modest gains with the slightly larger cases of the 338 RCM, 7 Rem mag and 300 win mag.

I tried Re 17 in my 06 with 180 Partitions yesterday. At 55 grains, I was getting 2826 from my 24" barrel M70. No pressure signs of any kind and decent accuracy. In my 300 SAUM, I broke 3000 with a 180 Partition, again with no pressure signs. I'm still leery and have backed down accordingly to 2800 in my 06, 2950 in the SAUM.

Huh??? Rifle barrels not designed to handle pressure at the muzzle end?? Please elaborate. Especially on how the pressure wouldn't show up at the breech.

Was a bit curious about that myself......

In theory, as the bullet moves down the barrel, the "powder" container increases in volume, which drops pressure due to the Ideal Gas Law.

I do know that the longer pressure curve is why shotgun shells made with "modern smokeless" have the printed warning on the box about shooting them in Damascus twist barrels. And I have an old family heirloom twist-barreled shotgun with a bulge toward the muzzle.

They were made to shoot black powder shells; black powder has a quick pressure spike. So the steel is thick toward the breech and thin toward the muzzle because with black powder, the pressure had subsided by the time the shot traveled down the bore.

Never heard of this with rifles though, and I'm pretty sure that before the bullet exits the muzzle the pressure is the same up and down the bore and the breech/bolt area would not be spared.

It would seem logical that the heavier chamber section of most rifles would be better able to contain a very brief momentary burst of 60,000 psi pressure (or greater) much more easily than could the thinner barrel walls further down the barrel.

My own understanding, however, is that certain powders create a longer maximum pressure peak and which can produce high speeds than do powders which peak more rapidly and for shorter periods of time. (By the same token, a lower maximum pressure load might also produce more speed if it maintained its high pressure for a longer period than a load which had a higher maximum, but very brief period of high pressure.)

The old DuPont/IMR Reloader's pamphlets were informative in this regard. They showed all or most of their rifle powders with many common cartridges. The maximum test pressures were generally very close. Faster powders in the larger cases never produce speeds anywhere near what the slower powders can even when the faster powders were fired in similar (or higher) pressures. The maximum pressure of a load is less important than maintaining a sufficiently high enough pressure over a longer period in order to keep the bullet accelerating.

smokepole,

Actually, modern pressure testing equipment has shown that black powder shotgun loads don't spike significantly quicker than modern smokeless loads. And it's also been proven that GOOD Damascus barrels will handle modern shotshells just fine.

The standard warning about shooting modern shotshells in Damascus barrels came about because there used to be a lot of cheap "twist" barrels on cheap shotguns. These weren't usually all that well maintained, either, and the cheaply made barrels allowed rust to work its way between the pieces of steel.

Thanks for the link, kinda looks as though R-17 was engineered like the powders used in Hornadys super performance ammo.
I used Barnes data for their 80 Gr. TTSX load & was getting 3500 fps out of a 22" kimber with no pressure indicators...Only fired 3 rounds of that load though.

For an interesting read on Damascus barrels and myth-busting, check out Stewart Bell's multi-part series "Finding out for Myself" in Double Gun and Single Shot Journal--basically, Bell took Damascus barrelled guns, some of which would qualify as wall hangers, and ran proof loads through them. Bell secured the guns in a lead-sled and triggered them remotely.

His conclusions? Basically: Myth Busted. The only guns that failed were those that had such serious internal corrosion or split stocks that they simply couldn't hold during recoil. The rest did fine. Bottom line--if you have a mechanically sound (and thoroughly inspected by a competent gunsmith) Damascus barrelled gun and you know how to handload low pressure shells, you ought to be out shooting it

Well, I guess my grandpa couldn't afford a shotgun with a good barrel; his was a knock-off of an English shotgun, made in the US, and he used the hell out of it. Had to replace the #1 firing pin (double-barrel, exposed hammer) with a hand-made pin. And there is a definite bulge in the barrel about 3/4 toward the muzzle.

Nevertheless and mythbusters notwithstanding, this is the reason for the printed warning on shotgun shells.



Yes, I can follow that part of the logic. But it would also seem logical that the pressure exerted at any point in the bullet's path down the barrel would also be exerted back at the breech/bolt and in the casing, so if there were pressure spikes they would show up there. That was my original point.

smokepole,

A bulged shotgun barrel can occur for many reasons. A bulge 3/4 of the way down is usually caused by a stuck wad. There's no way it was caused just by the pressure of a modern load that far down the bore.