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Rio Primers

6232 Views 28 Replies 10 Participants Last post by  Ned S
From: Carol Lister
Date: Mon, May 04, 2009 - 01:28 PM ET
Website Address:

Congratulations on not having split your chamber yet, Longshot. Obviously you haven't read everything that matters on the subject. Quote of a letter on the subject from Alliant:

"I am Dick Quesenberry, Product Manager for Alliant Canister Powder. Ben and I have discussed your e-mails and problems with Rio primers and our product. I apologize for the difficulty that you have encountered and appreciate you using our product.
We just completed work for the new revision of our Reloaders Guide, which was very badly needed. During this effort we tested all primers in a standard controlled load for both straight wall and tapered shells to correlate their brisance. The following conclusions were drawn from that effort:

· Primer brisance will vary from Lot to Lot within the same brand. Most vary within SAAMI safety limits but Rio was found to be extremely variable.

· We do not publish reloading recipes using Rio primers for the above reason

I have also talked to Kevin at Down Range (who happens to be a great guy) and he agrees with our findings.

If I was forced into recommending load data using the Rio 209, I would have to recommend loading like the Federal 209A and that may still give slightly higher velocities and pressures. ...

Call them an verify if you care to; I don't make this kind of stuff up just to annoy people like you. BTW, the original inquiries involved Promo, Red Dot and Clay Dot.

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I know this is a 2-year old thread, - but being an avid Rio hull reloader (lead) for Clay games for the last 4-5 years, and the fact that this thread comes up in Google, I thought I might chime in with some of my own thoughts and experiences.

Few thoughts to consider on C.L.'s old post (containing quoted text from Alliant's memo) ...

#1 It's complete chicanery for Alliant to state that the reason that they don't publish reload information using the Rio G-600 is because of "variance" (inter-lot or otherwise). This is the same company who has chosen to "group" (aka 'slash' as I call it) wads together in their published reloading recipes where the wad "groupings" don't even come close to each other in their published recipes performance wise. For example, Alliant publishes recipes that show: "12S3/DRF0" for the wad, whereas there is a problem with the Downrange DRF3 (12S3 clone) which causes off-sounders/bloopers, and SD's are in the hundreds. They do this for a lot of other Downrange wads as well.

It's debunk on Alliants part to cut a deal with Downrange to agree to "group" OEM wad data with Downrange clones on blind faith without testing the clone wad separately. Alliant doesn't do this for any other clone wad maker. Not that it matters (or even relevant here), but why doesn't Kevin from downrange publish his own testing data for all of his clone wads?

#3 As mentioned in this thread, Hodgdon does publish load data with the Rio G-600 primer (Clays recipes). If there were a problem with inter-lot variances with Rio primers, I would trust Hodgdon's word much more over Alliants (given situation #1 above).

#4 I do realize that Tom Armbrust published this article showing that the Rio had the highest EV (Extreme Variation) back in 2006: . But this is only one data point, and one particular recipe. Are there any other people, or testing labs who have done the same tests recently ? (And where is Tom's OEM to Downrange clone wad comparison tests ?) :rolleyes:

#4 Unless something has changed in the last 4-5 years with the Rio G-600 primers, I've actually found that the Rio primers, although supposedly hotter, are actually more consistent (velocity wise) than some of the other overseas primers (Fiocchi 616) in my own personal chronograph tests. For example, I just got done chrongraphing yet more Rio loads last Sunday (which also have been sent off to Precision Reloading for pressure testing) and although a chronograph can't test pressure, or pressure "variance", it can check velocity, and velocity variance. Here is that data:

Loader: brand new 20-ga MEC 9000 w/ new dedicated AutoMate, no powder baffle.
Chronograph: ProCrono Digital
Location: Renton Fish and Game, Renton, Washington
Outside temperature: 58 degrees F
Date: 5/29/2011
Time: ~3:15PM
Gun (20-bore) Limited Edition Browning Citori Upland Game series (525) w/ Browning/Briely Midas ext, SKT chokes.
Gun (12-bore) 30-inch Browning Citori XS Skeet, Carlson SKT/SKT chokes

S1) (control) 10 shots, 20-ga Remington 7/8's oz Gun Club (4-box Walmart Value pak)
1265 H
1223 L
1239 Avg
42 ES
12 SD


S5) 10 shots, 1F 12-ga Rio blue, 1-oz #8, Gualandi GU-1225 wad, 18.7 gn Alliant e3, Fio 616
1314 H
1290 L
1300 Avg
24 ES
7 SD

S6) 10 shots, 1F 12-ga Rio blue, 1-oz #8, Gualandi GU-1225 wad, 18.7 gn Alliant e3, Rio G-600
1308 H
1294 L
1298 Avg
14 ES
4 SD

Granted, my above load may be hot and over pressure (that is why they are off at Precision getting pressure tested), but this test, along with all my other tests (using other powders like Hodgdon's Clays) indicates that when compared to the Fiocchi Fio 616 primer, loads using the Rio G-600 always yields lower ES and SD numbers. Of course, this may simply mean that the Fiocchi Fio 616 may just be worse than the Rio G-600. But when I get the actual pressure test data back for the above loads (plus all the other loads sent in), I'll be sure report back here on the reported pressure EV's. It is interesting to note that the Avg velocity is a tad lower for the Rio primer loads (at least for that particular recipe).

All primers react differently to different powders (and different amounts) in different loads, we all realize that. But that is why I sent a large sampling in to get pressure tested, - to hopefuly 'duplicate' the work that Tom Armbrust did in the article in the above link I posted. I don't believe that there is a "one size fits all" general rule of thumb that should be proliferated around the forums about the Rio G-600 primers without ample data to support the claim(s) either way.
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I will be very interested in your results.
I only use the Rio Primer in Rio Hulls using Lightning Steel recipe 35 and 36 and they were very consistant in the Stoeger Condor and 935 only running 100 fps faster in the 935. I use the Rio Primer because of the oversized primer hole in these hulls. Ned S
Having read the above replies to the Rio primers i find that you cannot rely on velocity alone using a single pojectile chrony
after having 80 plus steel loadings in 12 gauge alone using various powders, wads and primers combinations
you can be in the postion of great velocity but the pressures are OTT.And the othe way round
Certain wads,primers will give low/high pressure and not very fast/to fast velocity you then need to move up a hull size to meet the happy medium. remember fast is ok Very fast OTT

A lot can be said for having loads tested for pressure and velocity before pattern testing

Really , I thought all powders burn going down the barrel. Also I have access to a pressure gun for testing my substitutes. All American Guns are pressure checked by the Gov't for an operationg pressure of around 14,300 psi in the UK before being sold. Ned S
When a cartridge is fired and powder is ignited the heat is converted into gas pressure.
Simple powders i.e nitrocellulse burn clean leaving very little residue in the barrel i.e lead clay /game loads
Slow burning in this case Aliant Steel steel loadins. leaves powder still burning up the barrel and does cause problems with velocity readings
from test guns hence the benifit of second velocity reading which can then be used to extrapolate back to 2.5m or the actual muzzle.
All reloading data seems to go down the same line in advising the reloader to stick to recipes and not substitue components
unless the state so.Unless you go to the expense of having them tested independently. This kit costs a lot of money

The Helarco VP60 and VP53 does not work with STEEL recipes as they are 1/8" too long and were made for the other slow burning powders. You just do not have room enough with the STEEL recipes. Also VP60 has been recalled because of the petals shearing off. VP65 works fine with STEEL. The Danes are using VP65 in their fast, fast loads. Ned S
baltz526 said:
I will be very interested in your results.
You bet. The data just came back. It is listed below with some of my observations:

Rio blue hull
7/8th's oz (25.34 gr) #8
Gualandi GU-1227
18.6 gn Alliant e3
Rio G-600 primer
Crimp depth: .074

Avg: 1332
SD: 06
EV: 14

Avg: 9230
SD: 284
EV: 700

Changing out the Rio G-600 to the Fiocchi Fio 616 in the above load, the performance degrades a bit to become:

Avg: 1326
SD: 10
EV: 27

Avg: 8940
SD: 487
EV: 1150

My aggressive/assertive 1-oz load of choice is (for the Benelli):

Rio blue hull
1 oz (28.05 gr) #8
Gualandi GU-1225
20.0 gn's Hodgdon's Clays
Rio G-600 primer
Crimp depth: .074

Avg: 1287
SD: 08
EV: 24

Avg: 9378
SD: 608
EV: 1610

Changing out the Rio G-600 to the Fiocchi Fio 616 in the above load, the performance degrades a bit more to become:

Avg: 1275
SD: 26
EV: 63

Avg: 9236
SD: 1335
EV: 3060

My passive/friendly 1-oz load of choice (for BT-99 G.C. etc) is:

Rio blue hull
1 oz (28.15 gr) #7-1/2
Gualandi GU-1225
19.2 gn's Hodgdon's Clays
Rio G-600 primer
Crimp depth: .074

Avg: 1251
SD: 16
EV: 42

Avg: 8626
SD: 532
EV: 1340

Changing out the Rio G-600 to the Fiocchi Fio 616 in the above load, the performance changes a bit to become:

Avg: 1245
SD: 10
EV: 25

Avg: 8402
SD: 666
EV: 1570

1) In all cases (these test cases), substituting the Fiocchi Fio 616 for the Rio G-600 appears to cause higher pressure variations.

2) In all cases except for one, the higher pressure variations appears to attribute to the higher velocity variations (SD and EV).

3) The Rio G-600 seems to perform it's best with Alliant's E3 (*) in the 7/8's oz load with a pressure SD of under 300.

* The e3 lot number used for this particular test suite is from 2006, back when they were stamped on the bottom of the keg in yellow ink (paint?)
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mokeman, thanks for the Rio primer info. Ned S
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