[nigonjac]

At a local shop the other day, and noticed they had some powder in stock. I usually use IMR4350 for my 270 Winchester, but am currently down to about a 1/4 pound left and haven’t seen any on the shelves for months. I saw they had IMR4955 and figured I’d give it a try. Does anyone have any personal experience with 4955 and loading for a 270 Winchester? Looking to work up a load with the Hornady 130 grain SST. Hornady does not list this powder in their manual, I contacted them and they said they have not tested with it-yet. I checked the Sierra manual for their 130 SPBT, and they have it listed with 45 minimum and 54.8 max as the extremes. Hodgdon has it listed as 55.8 minimum and 61.0 max compressed. I contacted Hodgdon about the rather large discrepancy and the only thing they sent back to me was was the load data I already had from their website. No explanation as to why data could be so different. I understand powder/bullet companies generally aren’t the same as far as published loads, but they generally are close. This does not seem to be the case with this powder which has me concerned as to where to even start safely. There are some conflicting reviews online which doesn’t help either. Hoping some of you may have experience with the 4955 “enduron” powder.
Would be using Winchester cases and CCI 250 primers.

Thanks,

 

[GSP7]

Never heard of it..... But Id use it, after I looked it up and read about it

IMR Enduron® 4955

IMR Enduron 4955 is a versatile, match-grade propellant with a mid-range burn speed that is in between IMR4451 and IMR7977. It is an extruded powder and provides top performance for big game cartridges like 25-06, 270 Winchester, 280 Remington and 300 Win Mag, among other cartridges. The main...

shop.hodgdon.com

This propellant performs comparably to Hodgdon H4831 but charge weights are materially different.

 

[jimboro]

. I wouldn't do this without a croni though. .. I hope you know how to read pressure signs. . If not .. learn to .. read up on it .. before you load anything. . ..but as always start low ..

 

[MikeG]

Wow, never heard of it, another "powder of the week." Good luck......

 

[Darkker]

Essentially all extruded powders had a few ingredients, which are reported as being less healthy than Kale.😉 In order to be able to sell to markets across the globe such as ball powders can; those ingredients had to go.
So General Dynamics rebuilt the extruded facility in Quebec for the change. "Enduron" is the buzz word Hodgdon markets those new formulation products under.

Cheers

 

[GSP7]

Huh ?

 

[Darkker]

What would you like clarified, the ingredients?

The removed products were:
2,4 Dinitrotoluene
Dibutyl Phthalate

The mover behind it is the EU and a CE certification stemming from the REACH program.


Nigonjac:
To your original question about the discrepancy. I wasn't aware of Sierra having done actual pressure testing in quite some time. Be interesting to know if this is calculated or what.

No it's not unthinkable for them(Hodg) to have some serious lot variations, especially given what was happening during the GD plant rebuild. But that is a bit excessive, so I suspect it's a calculation Vs testing issue.

Cheers

 

[unclenick]

I think Sierra has their max loads tested to be sure they don't exceed SAAMI numbers, but the loads themselves are developed in production guns and they don't change them if the pressure test comes out on the low side. These sorts of discrepancies are not uncommon among load manuals.

 

[recoil junky]

I think I'll stick with H4350, I have about 12 pounds left between one opened and one "sealed" 8 pounder. 😉

RJ

 

[MikeG]

Yes, I toured the Sierra plant a few years ago including the underground firing tunnel. Fascinating.

Was told that they work up loads, then send the max ones off to be pressure tested somewhere.

Their test guns were production receivers, with a heavy barrel that gets clamped into some sort of fixture.

 

[nigonjac]

After talking with Sierra they strongly recommended starting at 50 grains and working up. Said they used multiple lots of the stuff along with different barrels/brass/primers. I will start there and report back when I get a chance to have a nice range day.

 

[recoil junky]

After talking with Sierra they strongly recommended starting at 50 grains and working up. Said they used multiple lots of the stuff along with different barrels/brass/primers. I will start there and report back when I get a chance to have a nice range day.

Sounds good, Sierra, even though they make bullets, is one of the best about sharing knowledge. My "run ins" with them have always been very helpful.

RJ

 

[nigonjac]

Quick update. Did some three shot strings working up from 50 grains to 54 grains in .5 grain increments to compare to Sierra’s load data for velocity. Was not shooting for groups, just merely to check/verify velocity and pressure working up. No noticeable pressure signs at 54 grains, Sierra lists 54.8 as max. Average velocity from a browning xbolt, 22” barrel, 130 grain SST, seated .035 off the lands and 54.0 grain powder charge yielded 2905 FPS. Sierra’s manual figures 2940 FPS from a 24” barrel and that powder weight. Lots more testing to do, but so far I think Sierra hit the nail on the head, and hodgdons data should be taken with a small grain of salt.

 

[2ndtimer]

Quick update. Did some three shot strings working up from 50 grains to 54 grains in .5 grain increments to compare to Sierra’s load data for velocity. Was not shooting for groups, just merely to check/verify velocity and pressure working up. No noticeable pressure signs at 54 grains, Sierra lists 54.8 as max. Average velocity from a browning xbolt, 22” barrel, 130 grain SST, seated .035 off the lands and 54.0 grain powder charge yielded 2905 FPS. Sierra’s manual figures 2940 FPS from a 24” barrel and that powder weight. Lots more testing to do, but so far I think Sierra hit the nail on the head, and hodgdons data should be taken with a small grain of salt.

Based on nigonjac’s experience, it sounds like IMR-4955 is closer to the 4350’s than the 4831’s, Reloder 22 burn rate. I recently picked up a couple pounds of IMR-4451, based on reports that 4451 was close to 4350 burn rate, planning on using it in .270 Win and trying it in .300 Win Mag. From these reports, sounds like 4955 might have been a better choice. Has anyone tried both 4451 and 4955 in .270 Win and 300 Win Mag?

 

[MZ5]

Sierra shoots through universal receivers with pressure barrels and piezoelectric pressure test equipment, according to page 1 of their current manual (Edition VI). Here’s a brief quote from that page which, in this context, I think comports with Fair Use and forum rules:

To make the best use of these new testing facilities, a new (for Sierra) methodology was needed. We needed to ensure that every load we listed in the manual stayed under SAAMI or CIP Maximum Average Pressures. To accomplish this, we fired rounds to determine which load gave us the maximum pressure recommended, then we fired enough shots at that charge weight to ensure the propellant was stable at that velocity and pressure. If the propellant was not stable at that pressure, we would reduce it to a level that was. After the max load was safely established, we worked down to a safe minimum load in two or three increments. This method determined our upper and lower limits, allowing us to interpolate everything in between.

So, while Sierra used to use strictly production firearms, they now test their own loads in their universal receiver(s) and pressure barrels. THAT SAID, they still have data in the current manual that was developed in the past. Their 7mm BR Remington data is an example. Nevertheless, each load table clearly identifies whether they used a production rifle or a universal receiver.

My copy of Sierra’s 6th manual says they used a universal receiver for their 270 data. The data for 130-grain bullets (and the 135 SMK) and IMR 4955 is 44.8 - 53.2 grains, ranging in speed from 2500 - 2900 ft/sec.

What manual are you looking at, OP, for the Sierra data you list?

As to the difference between Hodgy’s data and Sierra’s: Clearly the bullets used are different, and maybe primer and case are also different. There are variations even with SAAMI-spec pressure barrels, and of course the powder lot may be different.

The prudent move here is to start with the lower charge range.

 

[unclenick]

Another problem with bullet maker load data is they like to lump all their similar weight bullets together in the velocity column featuring the same charge weight. You can guess that all the different bullet shapes didn't produce the exact same velocity with the same load. The numbers will reflect the bullet that produced the highest pressure and highest velocity with that same charge weight. The others will be approximate.

 

[nigonjac]

I have not gotten back to do some final testing. Accuracy has been first and foremost for me. Been busy with other things lately, but this is on the agenda to work up a final load. I will post my results when I finish load work up. Speed has always been secondary to me and I doubt if a deer will notice much whether it got hit by a 130 grain bullet going 3000 FPS or 2900 FPS when 90% of my hunting situations are within 100 yards

 

[Davers]

I think I'll stick with H4350, I have about 12 pounds left between one opened and one "sealed" 8 pounder. 😉

RJ

I've used both IMR-4350 & H-4350 which I like best for reloading 130 grain bullets in my .270. However I've not been able to find any since this past Christmas (2020).

 

[unclenick]

…90% of my hunting situations are within 100 yards

In that case, since some bullets don't perform their best at their maximum rated impact velocity, you may well find the lighter load of 4895 both reduces recoil and holds you down to nominal impact velocities. But before that, if you haven't already, I would call the bullet maker and find out what the optimal impact velocity is for the bullet and then try to find an accurate load that has the bullet impact at 100 yards at about that velocity.

 

[nigonjac]

In that case, since some bullets don't perform their best at their maximum rated impact velocity, you may well find the lighter load of 4895 both reduces recoil and holds you down to nominal impact velocities. But before that, if you haven't already, I would call the bullet maker and find out what the optimal impact velocity is for the bullet and then try to find an accurate load that has the bullet impact at 100 yards at about that velocity.

I would love to, with that being said I haven’t seen IMR 4895 on any of my local gun shop shelves in close to a year. And I can’t find it in me to pay 500-600 for an 8 lbs jug on gunbroker. The few pounds of 4895 I have left I have saved for my 223 and 308. I’m upset at myself I didn’t buy more when I had the chance.